Solid state light emitting devices including adjustable melatonin suppression effects

ABSTRACT

Solid state light emitting devices include multiple LED components providing adjustable melatonin suppression effects. Multiple LED components may be operated simultaneously according to different operating modes according to which their combined output provides the same or similar chromaticity, but provides melatonin suppressing effects that differ by at least a predetermined threshold amount between the different operating modes. Switching between operating modes may be triggered by user input elements, timers/clocks, or sensors (e.g., photosensors). Chromaticity of combined output of multiple LED components may also be adjusted, together with providing adjustable melatonin suppression effects at each selected combined output chromaticity.

TECHNICAL FIELD

Subject matter herein relates to solid state lighting devices, includingdevices with different emitters or groups of emitters being controllableto permit adjustment of melatonin suppression effects, and relates toassociated methods of making and using such devices.

BACKGROUND

In animals, circulating levels of the hormone melatonin (also knownchemically as N-acetyl-5-methoxytryptamine) vary in a daily cycle,thereby allowing the entrainment of the circadian rhythms of severalbiological functions. Melatonin is produced in humans by the pinealgland, a small endocrine gland located in the center of the brain. Themelatonin signal forms part of the system that regulates the sleep-wakecycle by chemically causing drowsiness and lowering the bodytemperature. Melatonin is commonly released in darkness (roughly 4-5hours before sleep), and its production is suppressed by exposure tolight. The light-dependent character of melatonin release andsuppression aids in falling asleep and waking up. Depending on theamount, melatonin can reduce core body temperature and inducesleepiness. Conversely, nighttime light exposure can increase bodytemperature, and enhance alertness and performance.

It is principally blue light (e.g., including blue light at a peakwavelength value between 460 to 480 nm, with some activity from about360 nm to about 600 nm), that suppresses melatonin and synchronizes thecircadian clock, proportional to the light intensity and length ofexposure. As shown in FIG. 1, the action spectrum for melatoninsuppression (with six individual data points represented as blacksquares) shows short-wavelength sensitivity that is very different fromthe known spectral sensitivity of the scotopic response curve(represented with a solid line) and photopic response curve (representedwith a dashed line)—being shifted approximately 50 nm and 100 nm to theleft of the scotopic and photopic response, respectively. (FIG. 1 wasoriginally presented in Thapan, Kavita, et al., “An action spectrum formelatonin suppression: evidence for a novel non-rod, non-conephotoreceptor system in humans,” J. Physiol. (2001), 535.1, pp.261-267.)

Circadian rhythm disorders may be associated with change in nocturnalactivity (e.g., nighttime shift workers), change in latitude (e.g., jetlag), and/or seasonal change in light duration (e.g., seasonal affectivedisorder, with symptoms including depression). The World HealthOrganization in 2007 named late night shift work as a probablecancer-causing agent. Melatonin is an anti-oxidant and suppressant oftumor development; accordingly, interference with melatonin levels mayincrease likelihood of developing cancer. It would be desirable toameliorate or reduce symptoms of circadian rhythm disorders and otherhealth conditions that may be associated with reduced melatonin levels.

With proliferation of tablet computers, electronic readers, and otherbacklit electronic devices, consumers are increasingly utilizing backlitdevices at nighttime hours, with the attendant potential for melatoninsuppression. Some consumers have reported that reading textual contentusing backlight electronic devices reduces sensation of drowsinessand/or interferes with falling asleep normally, in a manner notexperienced by reading conventional books. Although certain backlightdevices (e.g., computer monitors) permit users to control backlightcolor temperature, certain backlight color temperatures are notaesthetically pleasing to certain users.

Solid state light sources such as organic or inorganic light emittingdiodes (LEDs) or lasers may be used to provide colored (e.g., non-white)or white light (e.g., perceived as being white or near-white). Whitesolid state emitters are increasingly being used potential replacementsfor white incandescent or fluorescent lamps for reasons includingsubstantially increased efficiency and longevity. Solid state lightsources provide potential for very high efficiency relative toconventional incandescent or fluorescent sources, but have presentedchallenges in simultaneously achieving good efficacy, good colorreproduction, color variation among different emitters, and colorstability (e.g., with respect to variations in operating temperature).

Color reproduction is commonly measured using Color Rendering Index(CRI) or average Color Rendering Index (CRI Ra). In calculating CRI, thecolor appearance of 14 reflective samples is simulated when illuminatedby a reference illuminant and the test source, and a difference in colorappearance for each sample between the test and reference illuminationis computed. CRI therefore provides a relative measure of the shift insurface color and brightness of an object when lit by a particular lamp.The general color rendering index CRI Ra is a modified average utilizingthe first eight indices, all of which have low to moderate chromaticsaturation. The CRI Ra equals 100 (a perfect score) if the colorcoordinates and relative brightness of a set of test colors beingilluminated by the illumination system are the same as the coordinatesof the same test colors being irradiated by the reference radiator.Daylight has a high CRI (Ra of approximately 100), with incandescentbulbs also being relatively close (Ra greater than 95), and fluorescentlighting being less accurate (typical Ra of 70-80) for generalillumination use where the colors of objects are not important. For somegeneral interior illumination, a CRI Ra>80 is acceptable. CRI Ra>85, andmore preferably, CRI Ra>90, provides greater color quality.

Aspects relating to the present inventive subject matter may be betterunderstood with reference to the 1931 CIE (Commission International del'Eclairage) Chromaticity Diagram and/or the 1976 CIE ChromaticityDiagram, both of which are well-known and readily available to those ofordinary skill in the art. The CIE Chromaticity Diagrams map out thehuman color perception in terms of two CIE parameters x and y (in thecase of the 1931 diagram) or u′ and v′ (in the case of the 1976diagram). The 1931 CIE Chromaticity Diagram is reproduced at FIG. 2, andthe 1976 CIE Chromaticity Diagram (also known as (u′v′) chromaticitydiagram) is reproduced at FIG. 3. The spectral colors are distributedaround the edge of the outlined space, which includes all of the huesperceived by the human eye. The boundary line represents maximumsaturation for the spectral colors. The 1976 CIE Chromaticity Diagram issimilar to the 1931 Diagram, except that the 1976 Diagram has beenmodified such that similar distances on the Diagram represent similarperceived differences in color. Since similar distances on the 1976Diagram represent similar perceived differences in color, deviation froma point on the 1976 Diagram can be expressed in terms of thecoordinates, u′ and v′, e.g., distance from thepoint=(Δu′²+Δv′²)′^(1/2), and the hues defined by a locus of points thatare each a common distance from a specified hue consist of hues thatwould each be perceived as differing from the specified hue to a commonextent.

The chromaticity coordinates (i.e., color points) that lie along theblackbody locus (“BBL”) obey Planck's equation: E(λ)=A λ⁻⁵(e^(B/T)−1),where E is the emission intensity, λ is the emission wavelength, T thecolor temperature of the blackbody, and A and B are constants. Colorcoordinates that lie on or near the BBL yield pleasing white light to ahuman observer. The 1931 CIE Diagram (FIG. 2) includes temperaturelistings along the blackbody locus (embodying a curved line emanatingfrom the right corner). These temperature listings show the color pathof a blackbody radiator that is caused to increase to such temperatures.As a heated object becomes incandescent, it first glows reddish, thenyellowish, then white, and finally bluish. This occurs because thewavelength associated with the peak radiation of the blackbody radiatorbecomes progressively shorter with increased temperature, consistentwith the Wien Displacement Law. Illuminants which produce light that ison or near the BBL can thus be described in terms of their colortemperature.

The term “white light” or “whiteness” does not clearly cover the fullrange of colors along the BBL since it is apparent that a candle flameand other incandescent sources appear yellowish, i.e., not completelywhite. Accordingly, the color of illumination may be better defined interms of correlated color temperature (CCT) and in terms of itsproximity to the BBL. The pleasantness and quality of white illuminationdecreases rapidly if the chromaticity point of the illumination sourcedeviates from the BBL by a distance of greater than 0.01 in the x, ychromaticity system. This corresponds to the distance of about fourMacAdam ellipses, a standard employed by the lighting industry. Alighting device emitting light having color coordinates that are withinfour MacAdam step ellipses of the BBL and that has a CRI Ra>80 isgenerally acceptable as a white light for illumination purposes. Alighting device emitting light having color coordinates within seven oreight MacAdam ellipses of the BBL and that has a CRI Ra>70 is used asthe minimum standards for many other white lighting devices includingcompact fluorescent and solid state lighting devices. Generalillumination generally has a color temperature between 2,000 K and10,000 K, with the majority of lighting devices for general illuminationbeing between 2,700 K and 6,500 K.

The art continues to seek improved lighting devices that address one ormore limitations inherent to conventional devices.

SUMMARY

The present invention relates in various aspects to solid state (e.g.,LED) lighting devices including multiple solid state componentsproviding adjustable melatonin suppression effects.

In one aspect, the invention relates to a light emitting apparatuscomprising: a first LED component and a second LED component; whereinthe first LED component and the second LED component are arranged to beoperated in a first operating mode in which combined emissions of thefirst LED component and the second LED component (i) are within fourMacAdam ellipses of a target correlated color temperature, and (ii)embody a first melatonin suppression milliwatt per hundred lumens value;wherein the first LED component and the second LED component arearranged to be operated in a second operating mode in which combinedemissions of the first LED component and the second LED component (i)are within four MacAdam ellipses of the target correlated colortemperature, and (ii) embody a second melatonin suppression per hundredlumens value that is at least about 10 percent greater than the firstmelatonin suppression per hundred lumens value; and wherein the lightemitting apparatus comprises at least one of the following features (a)and (b): (a) at least one of the first LED component and the second LEDcomponent comprises at least one LED arranged to stimulate emissions ofat least one lumiphoric material; and (b) combined emissions of thefirst LED component and the second LED component when operated in thefirst operating mode embody a color rendering index (CRI) value of atleast about 80.

In another aspect, the invention relates to a light emitting apparatuscomprising: a first LED component and a second LED component; whereinthe first LED component and the second LED component are arranged to beoperated at or near a first target correlated color temperature in afirst operating mode in which combined emissions of the first LEDcomponent and the second LED component (i) are within four MacAdamellipses of the first target correlated color temperature, and (ii)embody a first melatonin suppression milliwatt per hundred lumens value;wherein the first LED component and the second LED component arearranged to be operated at or near the first target correlated colortemperature in a second operating mode in which combined emissions ofthe first LED component and the second LED component (i) are within fourMacAdam ellipses of the first target correlated color temperature, and(ii) embody a second melatonin suppression per hundred lumens value thatis at least about 10 percent greater than the first melatoninsuppression per hundred lumens value; wherein the first LED componentand the second LED component are arranged to be operated at or near asecond target correlated color temperature in a third operating mode inwhich combined emissions of the first LED component and the second LEDcomponent (i) are within four MacAdam ellipses of the second targetcorrelated color temperature, and (ii) embody a third melatoninsuppression milliwatt per hundred lumens value; wherein the first LEDcomponent and the second LED component are arranged to be operated at ornear the second target correlated color temperature in a fourthoperating mode in which combined emissions of the first LED componentand the second LED component (i) are within four MacAdam ellipses of thesecond target correlated color temperature, and (ii) embody a fourthmelatonin suppression per hundred lumens value that is at least about 10percent greater than the third melatonin suppression per hundred lumensvalue; and wherein the second target correlated color temperaturediffers from the first correlated color temperature preferably by atleast about 300K (more preferably by at least about 600K, still morepreferably by at least about 1000K).

In another aspect, the invention relates to a light fixture comprising alight emitting apparatus as disclosed herein, or an electronic deviceincluding a backlight comprising a light emitting apparatus as disclosedherein.

In another aspect, the invention relates to a method comprisingilluminating an object, a space, or an environment, utilizing a lightemitting apparatus as described herein.

In another aspect, the invention relates to a backlight arranged toilluminate a display panel arranged to display at least one of imagesand text, the backlight comprising: a first LED component; a second LEDcomponent; and a timer or clock arranged to trigger switching between afirst operating mode and a second operating mode; wherein in the firstoperating mode the first LED component and second LED component generatecombined emissions that (i) are within four MacAdam ellipses of a targetcorrelated color temperature, and (ii) embody a first melatoninsuppression milliwatt per hundred lumens value; and wherein in thesecond operating mode the first LED component and second LED componentgenerate combined emissions that (i) are within four MacAdam ellipses ofthe target correlated color temperature, and (ii) embody a secondmelatonin suppression per hundred lumens value that is at least about 10percent greater than the first melatonin suppression per hundred lumensvalue.

In another aspect, the invention relates to an electronic devicecomprising a backlight as disclosed herein and a display panel arrangedto be illuminated by the backlight. In another aspect, the inventionrelates to a method comprising illuminating a display panel utilizing abacklight as disclosed herein.

In another aspect, any of the foregoing aspects, and/or various separateaspects and features as described herein, may be combined for additionaladvantage. Any of the various features and elements as disclosed hereinmay be combined with one or more other disclosed features and elementsunless indicated to the contrary herein.

Other aspects, features and embodiments of the invention will be morefully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a line chart showing superimposed plots of the visible lightportion of the melatonin action spectrum (at left), the scotopicresponse curve (at center), and the photopic response curve (at right),depicting % relative sensitivity as a function of wavelength.

FIG. 2 is a 1931 CIE Chromaticity Diagram including representation ofthe blackbody locus, and further illustrating an approximately whitearea bounding the blackbody locus.

FIG. 3 is a 1976 CIE Chromaticity Diagram, also known as a (u′v′)chromaticity diagram.

FIG. 4A is a table including values for the melatonin action spectrum(relative units) and corresponding wavelengths.

FIG. 4B is a line chart for melatonin action spectrum showing the valuesdepicted in FIG. 4A.

FIG. 5 is a table including CCT, CRI, and melatonin suppressingmilliwatts per 100 lumens values for various light sources.

FIG. 6 is a plot of melatonin suppressing milliwatts per 100 lumensversus CCT obtained by modeling a solid state light source including ablue LED arranged to stimulate emissions of a yellow lumiphor incombination with a red LED, showing increasing milliwatts per 100 lumenswith increasing CCT.

FIG. 7A is a table identifying lumens, total lumens, relative lumens,CRI, and melatonin suppressing milliwatts per 100 lumens versus CRI at aCCT of 3000K obtained by modeling combined output of a first LEDcomponent including a blue LED arranged to stimulate emissions of ayellow lumiphor and a second LED component including a cyan LED arrangedto stimulate emissions of a red lumiphor.

FIG. 7B is plot of melatonin suppressing milliwatts per 100 lumensversus CRI at a CCT of 3000K using data listed in the table of FIG. 7A.

FIG. 8A is a table identifying lumens, total lumens, relative lumens,CRI, and melatonin suppressing milliwatts per 100 lumens versus CRI at aCCT of 5000K obtained by modeling combined output of a first LEDcomponent including a blue LED arranged to stimulate emissions of ayellow lumiphor and a second LED component including a cyan LED arrangedto stimulate emissions of a red lumiphor.

FIG. 8B is plot of melatonin suppressing milliwatts per 100 lumensversus CRI at a CCT of 5000K using data listed in the table of FIG. 8A.

FIG. 9A is a table identifying u′, v′ coordinates, CRI, R9, andmelatonin suppressing milliwatts per 100 lumens values at a CCT of 5000Kfor a first reference point on the blackbody locus, a second referencepoint to the right of the blackbody locus, and a third reference pointto the left of the blackbody locus.

FIG. 9B is a plot of the u′, v′ values for the three reference pointsidentified in FIG. 9A superimposed on a 1976 CIE chromaticity diagram.

FIG. 10A is a first perspective view of a solid state emitter packagethat may embody one or more LED components as defined herein accordingto one embodiment, the emitter package including multiple LEDs arrangedover an upper surface of a common substrate with multiple anodes andcathodes along a lower surface of the substrate.

FIG. 10B is a top plan view of a first subassembly of the emitterpackage of FIG. 10A, lacking a lens.

FIG. 100 is a top plan view of a second subassembly of the emitterpackage of FIG. 10A, lacking a lens, soldermask material, and LEDs.

FIG. 10D is a top plan view of a third subassembly of the emitterpackage of FIG. 10A, lacking a lens and LEDs.

FIG. 10E is a bottom plan view of each of the emitter package of FIG.10A and the subassemblies of FIGS. 1B, 1C, and 1D.

FIG. 10F is a right side elevation view of the first subassembly of FIG.10B.

FIG. 10G is a side cross-sectional view of the third subassembly of FIG.10D, taken along section lines “A”-“A” depicted in FIG. 10E.

FIG. 10H is an exploded right side elevation view of the emitter packageof FIG. 10A, separately depicting the lens registered with the firstsubassembly of FIG. 10B.

FIG. 10I is a second perspective view of the emitter package of FIG.10A.

FIGS. 11A to 11H illustrate a top plan schematic views of light emittingapparatuses including first and second LED components according tovarious embodiments.

FIG. 12 is a simplified schematic diagram illustrating interconnectionsbetween various components of a light emitting apparatus including firstand second LED components arranged in series and at least one controlcircuit.

FIG. 13 is a simplified schematic diagram illustrating interconnectionsbetween various components of a light emitting apparatus including firstand second LED components arranged in parallel and at least one controlcircuit.

FIG. 14 is a simplified plan view of a light emitting apparatusincluding multiple LED components and at least one control circuit.

FIG. 15 is a simplified plan view of another light emitting apparatusincluding multiple LED components and at least one control circuit.

FIG. 16 is a perspective assembly view of a display device includingdirect backlight including a two-dimensional array of light emittingdevices as described herein arranged to backlight a display (e.g., LCD)panel.

FIG. 17 is a perspective assembly view of a display device including awaveguide arranged to be lit along edges thereof by multiple lightemitting devices as described herein, with the waveguide arranged tobacklight a display (e.g., LCD) panel.

FIG. 18 is a schematic view of an array of light emitting devices asdescribed herein arranged to be controlled with a control element.

DETAILED DESCRIPTION

As noted previously, the art continues to seek improved lighting devicesthat address one or more limitations inherent to conventional devices.It would be desirable to permit adjustment of melatonin suppressioncharacteristics of lighting devices (including, but not limited to,backlights) to ameliorate or reduce symptoms of circadian rhythmdisorders or other health conditions, to avoid interference with sleepcycles, and/or to enhance nighttime worker alertness and performance. Itwould be desirable to provide one or more of the foregoing effects whilemaintaining high color rendering index values acceptably high for theintended use, or (in the case of backlights or other displays) toprovide adjustable melatonin suppression effects while maximizing gamutof displayed images and therefore improve color vividness. It would alsobe desirable to provide lighting devices permitting adjustment ofmelatonin suppression characteristics without dramatically altering CCT.If would also be desirable to provide lighting devices permittingadjustment of color temperature and also permitting adjustment ofmelatonin suppression characteristics. It would further be desirable toprovide lighting devices with high luminous efficacy and enhanced energyefficiency. It would also be desirable to provide lighting devices withreduced size, enhanced configuration flexibility, and/or extendedduration of service.

The present invention relates in various aspects to solid state (e.g.,LED) lighting devices including multiple solid state light emitting(e.g., LED) that are controllable to permit adjustment of melatoninsuppression effects. In certain embodiments, a light emitting apparatusincludes multiple LED components having substantially the same orsimilar chromaticity (e.g., each having a CCT within a specified numberof MacAdam ellipses of a target CCT) but having melatonin suppressioneffects that differ by a predetermined threshold (e.g., at least about5%, 10%, 15%, 20% 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 100%, 125%,150%, 200%, 300%, 400%, or more) may be separately controlled, to permitaggregated melatonin suppression effects of the light emitting apparatusto be adjusted. In certain embodiments, a control circuit may beprovided to permit switching between multiple predefined modes ofoperating a first LED component and a second LED component, wherein afirst operating mode is arranged to generate combined emissions of thefirst and second LED components within a specified number of (e.g.,preferably from one to six, more preferably four or fewer) MacAdamellipses of a target CCT and having a first melatonin suppressionmilliwatt per hundred lumens value, and wherein a second operating modeis arranged to generate combined emissions of the first and second LEDcomponents within a specified number of (e.g., preferably from one tosix, more preferably four or fewer) MacAdam ellipses of a target CCT andhaving a second melatonin suppression milliwatt per hundred lumens valuethat differs from the first melatonin suppression value by apredetermined threshold as described herein. In certain embodiments, alight emitting apparatus may provide adjustable CCT output, and furtherprovide adjustable msm/100 l at different CCT values. In certainembodiments, a light emitting apparatus may comprise a backlightarranged to illuminate a display panel, the backlight including firstand second LED components and a timer arranged to trigger switchingbetween a first operating mode and a second operating mode, wherein eachoperating mode is arranged to generate combined emissions of the firstand second LED components within a specified number of (e.g., preferablyfrom one to six, more preferably four or fewer) MacAdam ellipses of atarget CCT, but each operating mode provides a different melatoninsuppression characteristic (e.g., wherein a second melatonin suppressionmilliwatt per hundred lumens value associated with a second operatingmode differs from a first melatonin suppression milliwatt per hundredlumens value associated with a first operating mode by a predeterminedthreshold as described herein).

By providing multiple LED components having different melatoninsuppressing effects (and preferably with similar chromaticities) in asingle lighting device or apparatus, such components may be controlledto permit aggregated emissions to be adjusted for one or more desiredeffects. For example, if enhanced melatonin suppression effects aredesired (e.g., in order to promote wakefulness or alertness), then agreater proportion of total power may be supplied to one or moreindividual LED component(s) having greater melatonin suppression effectsrelative to one or more other LED component(s) of the same device havinglesser melatonin suppression effects. Conversely, if reduced melatoninsuppression effects are desired (e.g., in order to reduce potentialinterference with a user's ability to fall asleep), then a greaterproportion of total power may be supplied to one or more individual LEDcomponent(s) having lesser melatonin suppression effects relative to oneor more other LED component(s) of the same device having greatermelatonin suppression effects.

As noted previously, FIG. 1 includes six data points along the visiblelight portion of the melatonin action spectrum (a/k/a the melatoninaffecting region). By integrating the amount of light (milliwatts)within the melatonin action spectrum and dividing such value by thenumber of photopic lumens, a relative measure of melatonin suppressioneffects of a particular light source can be obtained. A scaled relativemeasure denoted “melatonin suppressing milliwatts per hundred lumens”may be obtained by dividing the photopic lumens by 100. The term“melatonin suppressing milliwatts per hundred lumens” or theabbreviations “msm/100 l” or “Mel mW/100 lumens” consistent with theforegoing calculation method are used throughout this application andthe accompanying figures. FIG. 4A is a table including values for themelatonin action spectrum (relative units) and correspondingwavelengths, while FIG. 4B is a line chart for melatonin action spectrumshowing the values depicted in FIG. 4A.

FIG. 5 is a table including CCT, CRI, and msm/100 l values for variouslight sources. As shown in FIG. 5, an incandescent lamp provides a veryhigh CRI value (˜100) at full brightness, provides a relatively lowmsm/100 l value (˜54) at such condition, but provides a much lowermsm/100 l value (˜25) when dimmed significantly. A Cree TrueWhite® LEDCR6 (including a blue LED arranged to stimulate emission of a yellowphosphor in combination with a red LED) performs similarly to anincandescent lamp, providing a CRI value (˜93) and msm/100 l value (˜46)at full brightness, with a reduced msm/100 l value (˜27) when dimmedsignificantly. Generally increasing msm/100 l values (provided inparentheses) are obtained from lighting apparatuses of the followingtypes: metal halide (72), tri-phosphor fluorescent (66), standardfluorescent (80), Cree cool white EasyWhite® LED including a blue LEDarranged to stimulate emissions of both yellow and red phosphors (90),sun on a white wall (120), daylight fluorescent (125), and blue sky(200). FIG. 6 is a plot of melatonin suppressing milliwatts per 100lumens versus CCT obtained by modeling a solid state light sourceincluding a blue LED arranged to stimulate emissions of a yellowlumiphor in combination with a red LED, showing increasing milliwattsper 100 lumens with increasing CCT. As is apparent from FIGS. 5 and 6,msm/100 l values generally increase with increasing CCT—as to beexpected, since increasing CCT corresponds to increased blue content,and the melatonin response spectrum has a peak value in the longwavelength portion (460-480) of the blue spectral range. Although FIG. 5demonstrates that msm/100 l values may be altered by substituting lightsources having different CCT values, individual light sources referencedin FIG. 5 are generally not capable of permitting adjustment of msm/100l values at a substantially constant CCT value.

While providing acceptably high CRI values together with adjustablemelatonin suppression effects may be desirable for general illumination,in other contexts (such as backlights for televisions, computermonitors, telephones, personal digital devices, table computers, and thelike) it may be desirable to provide adjustable melatonin suppressioneffects while maximizing (or not unduly restricting) gamut of displayedimages. In certain embodiments directed to backlights and backlighting,devices as disclosed herein may be adapted to output at least one gamutencompassing one or more of the following RGB color spaces: Adobe RGB,Apple RGB, CIE RGB, ColorMatch RGB, HDTV RGB (also known as sRGB), NTSCRGB, PAL/SECAM RGB, SGI RGB, SMPTE-C RGB, SMPTE-240M RGB, and Wide GamutRGB. Such color spaces are well understood by those skilled in the art,and are described by Pascale, D., “A Review of RGB Color Spaces . . .from xyY to R′G′B′″, available online athttp://www.babelcolor.com/download/A%20review%20of%20RGB%20color%20spaces.pdf.(Such reference is hereby incorporated by reference herein.) Inbacklight applications, colors of LEDs and lumiphoric materials maygenerally include narrow band LEDs or phosphors in order to maximizegamut of the displayed images and improve color vividness. This isopposed to general illumination applications where LED and phosphorcolors may preferably include at least one wide band phosphor (e.g., BSYtype using BOSE, YAG, or LuAG) chosen to provide suitably high colorrendering based on CRI.

Unless otherwise defined, terms used herein should be construed to havethe same meaning as commonly understood by one of ordinary skill in theart to which this invention belongs. It will be further understood thatterms used herein should be interpreted as having a meaning that isconsistent with their meaning in the context of this specification andthe relevant art, and should not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Embodiments of the invention are described herein with reference tocross-sectional, perspective, elevation, and/or plan view illustrationsthat are schematic illustrations of idealized embodiments of theinvention. Variations from the shapes of the illustrations as a result,for example, of manufacturing techniques and/or tolerances, are to beexpected, such that embodiments of the invention should not be construedas limited to particular shapes illustrated herein. This invention maybe embodied in different forms and should not be construed as limited tothe specific embodiments set forth herein. In the drawings, the size andrelative sizes of layers and regions may be exaggerated for clarity.

Unless the absence of one or more elements is specifically recited, theterms “comprising,” “including,” and “having” as used herein should beinterpreted as open-ended terms that do not preclude the presence of oneor more elements.

It will be understood that when an element such as a layer, region, orsubstrate is referred to as being “on” another element, it can bedirectly on the other element or intervening elements may be present.Moreover, relative terms such as “on”, “above”, “upper”, “top”, “lower”,or “bottom” are used herein to describe one structure's or portion'srelationship to another structure or portion as illustrated in thefigures. It will be understood that relative terms such as “on”,“above”, “upper”, “top”, “lower” or “bottom” are intended to encompassdifferent orientations of the device in addition to the orientationdepicted in the figures. For example, if the device in the figures isturned over, structure or portion described as “above” other structuresor portions would now be oriented “below” the other structures orportions.

The terms “solid state light emitter” or “solid state emitter” mayinclude a light emitting diode, laser diode, organic light emittingdiode, and/or other semiconductor device which includes one or moresemiconductor layers, which may include silicon, silicon carbide,gallium nitride and/or other semiconductor materials, a substrate whichmay include sapphire, silicon, silicon carbide and/or othermicroelectronic substrates, and one or more contact layers which mayinclude metal and/or other conductive materials.

Solid state light emitting devices according to embodiments of theinvention may include III-V nitride (e.g., gallium nitride) based LEDchips or laser chips fabricated on a silicon, silicon carbide, sapphire,or III-V nitride growth substrate, including (for example) devicesmanufactured and sold by Cree, Inc. of Durham, N.C. Such LEDs and/orlasers may be configured to operate such that light emission occursthrough the substrate in a so-called “flip chip” orientation. Such LEDand/or laser chips may also be devoid of growth substrates (e.g.,following growth substrate removal). LED chips useable with lightingdevices as disclosed herein may include horizontal devices (with bothelectrical contacts on a same side of the LED) and/or vertical devices(with electrical contacts on opposite sides of the LED).

Solid state light emitters as disclosed herein may be used individuallyor in groups to emit one or more beams to stimulate emissions of one ormore lumiphoric materials (e.g., phosphors, scintillators, lumiphoricinks, quantum dots, day glow tapes, etc.) to generate light at one ormore peak wavelength, or of at least one desired perceived color(including combinations of colors that may be perceived as white).Inclusion of lumiphoric (also called ‘luminescent’) materials inlighting devices as described herein may be accomplished by directcoating on lumiphor support elements or lumiphor support surfaces (e.g.,by powder coating, inkjet printing, or the like), adding such materialsto lenses, and/or by embedding or dispersing such materials withinlumiphor support elements or surfaces. Examples of lumiphoric materialsare disclosed, for example, in U.S. Pat. No. 6,600,175 and U.S. PatentApplication Publication No. 2009/0184616. Other materials, such as lightscattering elements (e.g., particles) and/or index matching materials,may be associated with a lumiphoric material-containing element orsurface. LED devices and methods as disclosed herein may include havemultiple LEDs of different colors, one or more of which may be whiteemitting (e.g., including at least one LED with one or more lumiphoricmaterials). One or more luminescent materials useable in devices asdescribed herein may be down-converting or up-converting, or can includea combination of both types.

The term “LED component” as used herein refers to one or more LEDsoptionally arranged to stimulate emissions of one or more lumiphoricmaterials. According to certain embodiments, a single LED component mayinclude multiple LEDs devoid of any lumiphor material, a single LEDarranged to stimulate emissions of a single lumiphoric material, asingle LED arranged to stimulate emissions of multiple lumiphoricmaterials, multiple LEDs arranged to stimulate emissions of a singlelumiphoric material, multiple LEDs arranged to stimulate emissions ofmultiple lumiphoric materials, or a single LED arranged to stimulateemissions of one or more lumiphoric materials in combination with one ormore additional LEDs not arranged to stimulate emissions of one or morelumiphoric materials. A LED component may include one or more lumiphoricmaterials located remotely from (e.g., spatially segregated from), butarranged to be stimulated by, one or more LEDs. (In certain embodiments,LEDs associated with multiple LED components may be arranged tostimulate one or more lumiphoric materials spatially segregated fromLEDs associated with the multiple LED components.) When a LED componentincludes one or more lumiphoric materials arranged to be stimulated byat least one LED, emissions of at least one LED may be only partiallyabsorbed by the one or more lumiphoric materials (wherein emissionsoutput by the LED component include an unabsorbed portion of emissionsof the at least one LED in combination with emissions of the one or morelumiphoric materials) according to certain embodiments, whereas in otherembodiments substantially all emissions of at least one LED are absorbedby one or more lumiphoric materials (wherein emissions output by the LEDcomponent consist of emissions of the one or more lumiphoric materials).When a LED component includes multiple LEDs, such LEDs may be controlledas a group according to certain embodiments, whereas such LEDs may beseparately controlled according to other embodiments.

In certain embodiments, control of one or more solid state emittergroups or sets may be responsive to a control signal (optionallyincluding at least one sensor arranged to sense electrical, optical,and/or thermal properties and/or environmental conditions), a timer orclock signal, and/or at least one user input, and a control system maybe configured to selectively provide one or more control signals to atleast one current supply circuit. In various embodiments, current todifferent circuits or circuit portions may be pre-set, user-defined, orresponsive to one or more inputs or other control parameters.

The term “substrate” as used herein in connection with lightingapparatuses refers to a mounting element on which, in which, or overwhich multiple solid state light emitters (e.g., emitter chips) may bearranged or supported (e.g., mounted). Exemplary substrates useful withlighting apparatuses as described herein include printed circuit boards(including but not limited to metal core printed circuit boards,flexible circuit boards, dielectric laminates, and the like) havingelectrical traces arranged on one or multiple surfaces thereof, supportpanels, and mounting elements of various materials and conformationsarranged to receive, support, and/or conduct electrical power to solidstate emitters. A unitary substrate may be used to support multiple LEDcomponents (e.g., multiple groups of solid state emitter components),and may further be used to support (and/or to be in electricalcommunication with) various circuit elements (e.g., control circuits,driver circuit elements, rectifier circuit elements, power supplyelements, current limiting circuit elements, current diverting circuitelements, dimmer circuit elements, surge protection elements,electrostatic discharge elements, and the like), sensors, timers/clocks,and/or user input elements. In certain embodiments, a substrate mayinclude multiple emitter mounting regions each arranged to receive oneor more solid state light emitters and/or LED components. In certainembodiments, substrates may include conductive regions arranged toconduct power to solid state light emitters or solid state light emittergroups arranged thereon or there over. In other embodiments, substratesmay be insulating in character, and electrical connections to solidstate emitters may be provided by other means (e.g., via conductors notassociated with substrates).

In certain embodiments, a substrate, mounting plate, or other supportelement on or over which multiple LED components may be mount maycomprise one or more portions of, or all of, a printed circuit board(PCB), a metal core printed circuit board (MCPCB), a flexible printedcircuit board, a dielectric laminate (e.g., FR-4 boards as known in theart) or any suitable substrate for mounting LED chips and/or LEDpackages. In certain embodiments, a substrate may comprise one or morematerials arranged to provide desired electrical isolation and highthermal conductivity. In certain embodiments, at least a portion of asubstrate may include a dielectric material to provide desiredelectrical isolation between electrical traces or components of multipleLED sets. In certain embodiments, a substrate can comprise ceramic suchas alumina, aluminum nitride, silicon carbide, or a polymeric materialsuch as polyimide, polyester, etc. In certain embodiments, substrate cancomprise a flexible circuit board or a circuit board with plasticallydeformable portions to allow the substrate to take a non-planar (e.g.,bent) or curved shape allowing for directional light emission with LEDchips of one or more LED components also being arranged in a non-planarmanner.

In certain embodiments, a substrate can be provided in a relativelysmall form factor in any desired shape (e.g., square, round, non-square,non-round, symmetrical and/or asymmetrical). Examples of smallfootprints or form factors of multi-emitter solid state light emittingapparatuses (e.g., including LED packages) including multiple LEDcomponent as described herein may include less than 5 cm², less than 3cm², less than 2 cm², less than 1 cm², less than 0.5 cm², less than 0.3cm², or less than 0.25 cm². LED chips of any suitable size or formfactor may be included in a multi-emitter lighting emitting apparatus,including chips having a width of up to about 2000 microns, up to about1000 microns, up to about 500 microns, up to about 350 microns, or anyother suitable size. In other embodiments, a substrate may comprise alarger form factor, such as may be suitable for replacement of elongatedfluorescent tube-type bulbs or replacement of relatively large lightfixtures.

In certain embodiments, one or more LED components can include one ormore “chip-on-board” (COB) LED chips and/or packaged LED chips that canbe electrically coupled or connected in series or parallel with oneanother and mounted on a portion of a substrate. In certain embodiments,COB LED chips can be mounted directly on portions of substrate withoutthe need for additional packaging. In certain embodiments, LEDcomponents may use packaged LED chips in place of COB LED chips. Forexample, in certain embodiments, LED components may utilize compriseserial or parallel arrangements of XLamp XM-L High-Voltage (HV) LEDpackages available from Cree, Inc. of Durham, N.C. Lighting devices asdisclosed herein may include LED components including solid stateemitters or groups of solid state emitters configured in variousarrangements depending upon the application and/or voltage rangedesired. In certain embodiments, separately controllable solid stageemitters or groups of solid state emitters may be configured to operateat different voltages. Examples of possible operating voltages include,but are not limited to, 3V, 6V, and 12V.

In certain embodiments, one or more reflector elements (eithersymmetrical or asymmetrical in nature) may be attached to, integrallyformed with, or otherwise associated with a substrate and arranged toreflect emissions from one or more (preferably multiple) LED components,such as to direct emissions in one or more desired directions and/orgenerate one or more desired beam patterns. In certain embodiments, oneor more optical elements may be arranged to receive emissions from oneor more (preferably multiple) LED components, and arranged to interactwith such emissions to provide desired (e.g., light mixing, focusing,collimation, dispersion, and/or beam shaping) utility in eithersymmetrical or asymmetrical fashion. In certain embodiments, one or moreoptical elements may be provided in addition to one or more reflectorelements.

In certain embodiments, lighting devices or light emitting apparatusesas described herein may include at least one LED with a peak wavelengthin the visible range. In certain embodiments, one or more shortwavelength solid state emitters (e.g., blue and/or cyan LED) may be usedto stimulate emissions from at least one lumiphoric material, a mixtureof lumiphoric materials, or discrete layers of lumiphoric material(e.g., including red, yellow, and green lumiphoric materials). Incertain embodiments, at least two independently controlled short ormedium wavelength (e.g., blue, cyan, or green) LEDs may be provided in asingle LED component with at least one LED arranged to stimulateemissions of at least one lumiphors, which may comprise the same ordifferent materials in the same or different amounts or concentrationsrelative to the LEDs. In certain embodiments, multiple electricallyactivated (e.g., solid state) emitters are provided, with groups ofemitters being separately controllable relative to one another. Incertain embodiments, one or more groups of solid state emitters asdescribed herein may include at least a first LED chip comprising afirst LED peak wavelength, and include at least a second LED chipcomprising a second LED peak wavelength that differs from the first LEDpeak wavelength by at least 10 nm, by at least 20 nm, or by at least 30nm (preferably, but not necessarily, in the visible range). In certainembodiments, solid state emitters with peak wavelengths in theultraviolet (UV) range may be used to stimulate emissions of one or morewavelength conversion materials. Emitters having similar outputwavelengths may be selected from targeted wavelength bins. Emittershaving different output wavelengths may be selected from differentwavelength bins, with peak wavelengths differing from one another by adesired threshold (e.g., at least 20 nm, at least 30 nm, at least 50 nm,or another desired threshold).

In certain embodiments, at least one LED component (and preferablymultiple LED components) includes at least one solid state emitterarranged to stimulate at least one lumiphor, such as may be used togenerate white or near-white light. In certain embodiments, one or moreLED components may include one of one or more of the following items:

-   -   a blue shifted yellow (“BSY”) component including a principally        blue solid state emitter (e.g., preferably including a peak        wavelength in a range of from about 410 nm to about 480 nm, more        preferably from about 455 nm to about 480 nm, still more        preferably from about 465 nm to about 480 nm) arranged to        stimulate emissions of a principally yellow lumiphor (e.g.,        preferably including a peak wavelength in a range of from 561 nm        to 590 nm);    -   a blue shifted (yellow plus red) (“BS(Y+R)”) component including        a principally blue solid state emitter arranged to stimulate        emissions of a principally yellow lumiphor and a principally red        lumiphor (e.g., preferably including a peak wavelength in a        range of from about 591 nm to about 690 nm);    -   a blue shifted red (“BSR”) component including a principally        blue solid state emitter arranged to stimulate emissions of a        principally red lumiphor;    -   a cyan shifted red (“CSY”) component including a principally        cyan solid state emitter (e.g., preferably including a peak        wavelength in a range of from about 481 nm to about 505 nm)        arranged to stimulate emissions of a principally yellow        lumiphor;    -   a cyan shifted red (“CSR”) component including a principally        cyan solid state emitter arranged to stimulate emissions of a        principally red lumiphor;    -   a green shifted red (“GSR”) component including a principally        green solid state emitter (e.g., including a peak wavelength in        a range of from about 506 nm to about 560 nm) arranged to        stimulate emissions of a principally red lumiphor;    -   a UV shifted blue plus yellow (“UV(B+Y)”) component including a        principally ultraviolet solid state emitter (e.g., having a peak        wavelength in the ultraviolet range, preferably shorter than        about 400 nm) arranged to stimulate emissions of a principally        blue lumiphor and a principally yellow lumiphor;    -   a UV shifted blue plus red (“UV(B+R)”) component including a        principally ultraviolet solid state emitter arranged to        stimulate emissions of a principally blue lumiphor and a        principally red lumiphor;    -   a UV shifted cyan plus yellow (“UV(C+Y)”) component including a        principally ultraviolet solid state emitter arranged to        stimulate emissions of a principally cyan lumiphor and a        principally yellow lumiphor;    -   a UV shifted cyan plus red (“UV(C+R)”) component including a        principally ultraviolet solid state emitter arranged to        stimulate emissions of a principally cyan lumiphor and a        principally red lumiphor;    -   a UV shifted green plus red (“UV(G+R)”) component including a        principally ultraviolet solid state emitter arranged to        stimulate emissions of a principally green lumiphor and a        principally red lumiphor;    -   supplementation of any of the foregoing items with at least one        supplemental electrically activated solid state emitter (e.g.,        LED), preferably having a peak wavelength in the visible range        of any suitable color; and    -   supplementation of any of the foregoing items with at least one        additional lumiphor having a peak wavelength of any suitable        color.        Although the inventive subject matter is not limited to use of        the foregoing components, light emitting apparatuses including        any suitable combination of first and second components        independently selected from the foregoing items are        contemplated.

In certain embodiments, at least one first LED component may include oneor more (preferably multiple) solid state emitters arranged to stimulateat least one lumiphor, and such at least one first LED component may bearranged in a single device with at least one second component includingmultiple LEDs of different peak wavelengths and not arranged tostimulate any lumiphor. For example, the second LED component mayinclude a RGB component, or red, green, and blue LEDs, or any othersuitable combination of differently-colored LEDs that may be arranged togenerate white or near-white light.

Since the melatonin response spectrum has a peak value in the longwavelength portion (460 to 480 nm subset) of the blue spectral range,close to the cyan range, in certain embodiments, at least one LEDcomponent includes at least one principally blue LED and/or at least oneblue lumiphor having a peak wavelength preferably in a range of fromabout 455 nm to about 480 nm, more preferably in a range of from about465 to about 480 nm. Given the proximity of cyan (generally spanning 481nm to 505 nm) to the peak of the melatonin response spectrum, in certainembodiments, at least one LED component includes at least oneprincipally cyan LED and/or at least one cyan lumiphor having a peakwavelength in a range of from about 481 nm to about 505 nm.

Addition of at least one supplemental (e.g., red) emitter may be usefulto enhance warmth of BSY or white emissions and/or improve colorrendering. In certain embodiments, separate electrically activatedconstituents of one or more LED components (e.g., BSY and red emitters)may be separately controlled, as may be useful to adjust colortemperature and/or to maintain a desired color point as temperatureincreases, optionally in response to signals received from one or moretemperature sensors. In various embodiments, separate electricallyactivated constituents (e.g., BSY and red constituents) may becontrolled together in a single LED component, or may be placed indifferent LED components that are separately controlled. One or moresupplemental solid state emitters and/or lumiphors of any suitable color(or peak wavelength) may be substituted for one or more redlight-emitting components, or may be provided in addition to one or morered light-emitting components.

In certain embodiments, a solid state lighting device may include one ormore groups or sets of BSY light emitting components supplemented withone or more supplemental emitters, such as long wavelength blue, cyan,green, yellow, amber, orange, red or any other desired colors. Presenceof a cyan solid state emitter and/or a cyan lumiphor is particularlydesirable in certain embodiments to permit adjustment or tuning of colortemperature of one or more LED components of a light emitting apparatus,since the tie line for a cyan solid state emitter having a ˜487 nm peakwavelength is substantially parallel to the blackbody locus for a colortemperature of less than 3000K to about 4000K. (See, e.g., FIG. 2,wherein an imaginary line drawn from the 487 nm value at the left gamutboundary to the blackbody locus is substantially parallel to the BBLfrom ˜3000K to ˜4000K.) In certain embodiments, one or more constituentsof a LED component may be controlled separately, such as may be usefulto adjust intensity, permit tuning of output color, permit tuning ofcolor temperature, and/or affect dissipation of heat generated by thelight emitting components.

In certain embodiments, one or more LED components as described hereinmay include multiple independently controllable BSY emitters, optionallysupplemented with one or more additional LEDs and/or lumiphors. Incertain embodiments, multiple BSY emitters present in one or morecomponents of a single lighting device (e.g., whether in the same ordifferent components, optionally within one or more solid state emitterpackages) may include blue LEDs with different peak wavelengths (e.g.,LED peak wavelengths that differ from one another by one of thefollowing wavelength thresholds: at least 5 nm, at least 10 nm, at least15 nm, at least 20 nm, at least 25 nm, at least 30 nm, at least 35 nm,and at least 40 nm), and/or yellow lumiphors with different peakwavelengths (e.g., lumiphor peak wavelengths that differ from oneanother by one of the following wavelength thresholds: at least 5 nm, atleast 10 nm, at least 15 nm, at least 20 nm, at least 25 nm, at least 30nm, at least 35 nm, and at least 40 nm).

The expression “peak wavelength”, as used herein, means (1) in the caseof a solid state light emitter, to the peak wavelength of light that thesolid state light emitter emits if it is illuminated, and (2) in thecase of a lumiphoric material, the peak wavelength of light that thelumiphoric material emits if it is excited.

In certain embodiments, a first blue or shorter wavelength LED and aseparately controllable second blue or shorter wavelength LED may bothbe arranged to stimulate emissions of a remote lumiphor (e.g., includinga yellow lumiphor such as may include a YAG phosphor) spatiallyseparated from both LEDs, and combined with a red emitting LED. Peakwavelengths of the first LED and second LED may differ from one anotherby preferably at least about 20 nm, at least about 25 nm, at least about30 nm, at least about 35 nm, at least about 40 nm, at least about 45 nm,or at least about 50 nm. For example, a first LED may include arelatively longer (blue) peak wavelength (e.g., preferably from about430 nm to about 470 nm, more preferably from about 440 nm to about 460nm, more preferably from about 445 nm to about 455 nm, more preferablyabout 450 nm) and the second LED may include a relatively shorter (blueor near UV) peak wavelength (e.g., preferably from about 390 nm to about425 nm, more preferably from about 395 nm to about 420 nm, morepreferably from about 400 nm to about 415 nm, more preferably from about400 to about 410 nm). If a first LED is a longer wavelength blue (e.g.,peak wavelength ˜450 nm) the second LED is a shorter wavelength blue ornear UV (e.g., peak wavelength ˜410 nm), the first and second LEDs areindependently controllable and arranged to stimulate emissions of ayellow YAG phosphor (and combined with a red LED) in order to generatewarm white light having a CCT of around 2700K, then the msm/100 l valuefor the resulting combination is expected to be ˜40 msm/100 l when thefirst LED is operated, whereas the msm/100 l value for the resultingcombination is expected to be ˜100 msm/100 l. The resulting differencein melatonin suppression effects from a value of 40 msm/100 l to 100msm/100 l represents an increase of about 150%. In another embodiment,if an even shorter wavelength (e.g., ˜400 nm peak wavelength) second LEDis substituted for the 410 nm peak wavelength in the foregoing device,then the resulting combination is expected to output light having amsm/100 l value of about 200 msm/100 l at a CCT of 2700. The resultingdifference in melatonin suppression effects from a value of about 40msm/100 l to about 200 msm/100 l represents an increase of about 400%.This demonstrates that selection and independent operation of LEDs withdifferent peak wavelengths may be used to significantly affect melatoninsuppression effects of a lighting device.

In certain embodiments, light emitting apparatuses as disclosed hereinmay be used as described in U.S. Pat. No. 7,213,940, which is herebyincorporated by reference. In certain embodiments, a combination oflight (aggregated emissions) exiting a lighting emitting apparatusincluding multiple LED components as disclosed herein, may, in anabsence of any additional light, produce a mixture of light having x, ycolor coordinates within an area on a 1931 CIE Chromaticity Diagramdefined by points having coordinates (0.32, 0.40), (0.36, 0.48), (0.43,0.45), (0.42, 0.42), (0.36, 0.38). In certain embodiments, combinedemissions from a lighting emitting apparatus as disclosed herein mayembody at least one of (a) a color rendering index (CRI Ra) value of atleast 85, and (b) a color quality scale (CQS) value of at least 85.

Some embodiments of the present invention may use solid state emitters,emitter packages, fixtures, luminescent materials/elements, power supplyelements, control elements, and/or methods such as described in U.S.Pat. Nos. 7,564,180; 7,456,499; 7,213,940; 7,095,056; 6,958,497;6,853,010; 6,791,119; 6,600,175, 6,201,262; 6,187,606; 6,120,600;5,912,477; 5,739,554; 5,631,190; 5,604,135; 5,523,589; 5,416,342;5,393,993; 5,359,345; 5,338,944; 5,210,051; 5,027,168; 5,027,168;4,966,862, and/or 4,918,497, and U.S. Patent Application PublicationNos. 2009/0184616; 2009/0080185; 2009/0050908; 2009/0050907;2008/0308825; 2008/0198112; 2008/0179611, 2008/0173884, 2008/0121921;2008/0012036; 2007/0253209; 2007/0223219; 2007/0170447; 2007/0158668;2007/0139923, and/or 2006/0221272; with the disclosures of the foregoingpatents and published patent applications being hereby incorporated byreference as if set forth fully herein.

The expressions “lighting device” and “light emitting apparatus”, asused herein, are not limited, except that they are capable of emittinglight. That is, a lighting device or light emitting apparatus can be adevice which illuminates an area or volume, e.g., a structure, aswimming pool or spa, a room, a warehouse, an indicator, a road, aparking lot, a vehicle, signage, e.g., road signs, a billboard, a ship,a toy, a mirror, a vessel, an electronic device, a boat, an aircraft, astadium, a computer, a remote audio device, a remote video device, acell phone, a tree, a window, an LCD display, a cave, a tunnel, a yard,a lamppost, or a device or array of devices that illuminate anenclosure, or a device that is used for edge or back-lighting (e.g.,backlight poster, signage, LCD displays), light bulbs, bulb replacements(e.g., for replacing AC incandescent lights, low voltage lights,fluorescent lights, etc.), outdoor lighting, security lighting, exteriorresidential lighting (wall mounts, post/column mounts), ceilingfixtures/wall sconces, under cabinet lighting, lamps (floor and/or tableand/or desk), landscape lighting, track lighting, task lighting,specialty lighting, ceiling fan lighting, archival/art display lighting,high vibration/impact lighting-work lights, etc., mirrors/vanitylighting, or any other light emitting devices. In certain embodiments,lighting devices or light emitting apparatuses as disclosed herein maybe self-ballasted.

The inventive subject matter further relates in certain embodiments toan illuminated enclosure (the volume of which can be illuminateduniformly or non-uniformly), comprising an enclosed space and at leastone lighting device or light emitting apparatus as disclosed herein,wherein at least one lighting device or light emitting apparatusilluminates at least a portion of the enclosure (uniformly ornon-uniformly). The inventive subject matter further relates to anilluminated area, comprising at least one item, e.g., selected fromamong the group consisting of a structure, a swimming pool or spa, aroom, a warehouse, an indicator, a road, a parking lot, a vehicle,signage, e.g., road signs, a billboard, a ship, a toy, a mirror, avessel, an electronic device, a boat, an aircraft, a stadium, acomputer, a remote audio device, a remote video device, a cell phone, atree, a window, a LCD display, a cave, a tunnel, a yard, a lamppost,etc., having mounted therein or thereon at least one lighting device orlight emitting apparatus as described herein. Methods includeilluminating an object, a space, or an environment, utilizing one ormore lighting devices or light emitting apparatuses as disclosed herein.

In certain embodiments, a lighting apparatus includes multiple LEDcomponents having different melatonin suppression effects, butpreferably having similar chromaticities (e.g., within a specifiednumber (e.g., preferably seven or fewer, more preferably four or fewer,more preferably three or fewer, or two or fewer) MacAdam ellipses of atarget CCT), are arranged on a common substrate or mounting plate, andare subject to being controlled by one or more control circuits. Incertain embodiments, a lighting apparatus includes multiple LEDcomponents, wherein combined emissions of the multiple components are ator near (e.g., within a number of MacAdam ellipses as specified herein)a target correlated color temperature in a range of from about 2000K to8000K, more preferably in a range of from about 2500K to 6000K. Incertain embodiments, each LED component is separately arranged to outputemissions at or near (e.g., within a number of MacAdam ellipses asspecified herein) a target correlated color temperature in a range offrom about 2000K to 8000K, more preferably in a range of from about2500K to 6000K.

In certain embodiments, a lighting apparatus as disclosed hereinincludes multiple LED components arranged in an array (e.g., atwo-dimensional array). In certain embodiments, emitters of a first LEDcomponent may be interspersed with emitters of a separately controllablesecond LED component (e.g., with emitters of a first LED componentarranged in a two-dimensional array that is superimposed with emittersof a second LED component arranged in a two dimensional array), such asmay be beneficial to promote color mixing, optionally aided with one ormore diffuser elements.

In certain embodiments, individual emitters within a multi-emitter LEDcomponent may be arranged in series, in parallel, or in aseries-parallel relationship. In certain embodiments, multiple LEDcomponents of a solid state light emitting apparatus may be arranged inseries, in parallel, or in series-parallel relationship. In certainembodiments, a light emitting apparatus as described herein may includeat least one control circuit arranged to independently supply current(or adjust relative supply of current) to at least one of the first LEDcomponent and the second LED component to operate (e.g., simultaneously)the first LED component and the second LED component according to thefirst operating mode or the second operating mode (and optionallyaccording to third, fourth, and/or additional operating modes). Incertain embodiments, modulation of current and/or duty cycle may beperformed with one or more current bypass and/or current shunt elementsthat may be optionally controlled by one or more control circuits.

In certain embodiments, at least one control circuit arranged to controlone or more LED components may include a current supply circuitconfigured to independently apply an on-state drive current to eachindividual solid state emitter or each individual LED component. Incertain embodiments, drive currents may be pulsed, such as with pulsewidth modulation. Control of one or more solid state emitters may beresponsive to a control signal (optionally including at least one sensorarranged to sense electrical, optical, and/or thermal properties and/orenvironmental conditions), and a control system may be configured toselectively provide one or more control signals to at least one currentsupply circuit. In various embodiments, current to different circuits orcircuit portions may be pre-set, user-defined, or responsive to one ormore inputs or other control parameters.

In certain embodiments, one or more control circuit elements may beoperated or controlled responsive to one or more user input elements,one or more timer or clock elements, and/or one or more sensor elements(e.g., temperature sensing element, photosensors, etc.). One or moreinput elements, timer or clock elements, and/or sensors may be used totrigger switching between at least first and second modes of a lightemitting apparatus as described herein. Multiple elements of thepreceding group may be provided. In certain embodiments, one or morecontrol circuit elements, user input elements, timer or clock elements,and/or sensor elements may be supported by and/or in electricalcommunication with a substrate of a lighting apparatus. In certainembodiments, a photosensor may be arranged to receive ambient light,while being shielded or otherwise placed to prevent receipt of directlight emissions from a first LED component and a second LED component.In certain embodiments, a photosensor may be used to trigger switchingbetween operating modes of a light emitting apparatus as describedherein, such as by adjusting current and/or duty cycle of different LEDcomponents responsive to presence, absence, or level of ambient light,or responsive to presence or absence of motion (e.g., as indicative ofpresence or absence of a person, a vehicle, or another object).

In certain embodiments, a user input element arranged to receive a userinput may be in wired or wireless communication with a light emittingapparatus. In certain embodiments, a user input element, timer/clock,sensing element, and/or control circuit may include a dedicated orgeneral purpose computer, or a dedicated or general purpose personalelectronic device, arranged to implement software or other machinereadable instructions to implement desired input and/or controlfunctionality for use with a light emitting apparatus as disclosedherein. In certain embodiments, a memory or other data logging elementor apparatus may be associated with a light emitting apparatus asdisclosed herein and arranged to receive and store informationindicative of binning, performance specifications, operatingcharacteristics, operating parameters, operating time, calibrationparameters, maintenance requirements, or other information relating toproduction, calibration, operation, maintenance, and/or servicing.

In certain embodiments, a light emitting apparatus may include a firstLED component and a second LED component, wherein the first LEDcomponent and the second LED component are arranged to be operated in afirst operating mode in which combined emissions of the first LEDcomponent and the second LED component (i) are within four MacAdamellipses of a target correlated color temperature, and (ii) embody afirst melatonin suppression milliwatt per hundred lumens value, andwherein the first LED component and the second LED component arearranged to be operated in a second operating mode in which combinedemissions of the first LED component and the second LED component (i)are within four MacAdam ellipses of the target correlated colortemperature, and (ii) embody a second melatonin suppression per hundredlumens value that is preferably at least about 10 percent greater (morepreferably at least about 20 percent, at least about 30 percent, atleast about 40 percent, or at least about 50 percent greater) than thefirst melatonin suppression per hundred lumens value. Combined emissionsof a light emitting apparatus when operated in the first operating modepreferably embodies a color rendering index (CRI) value of at leastabout 80 (more preferably a value of at least about 85, still morepreferably a value of at least about 90). Given the relatively narrowwavelength (e.g., full-width half-max) output of most electricallyactivated solid state emitters (including LEDs), it may be challengingto obtain high CRI values of 80 or more without use of lumiphoricmaterials unless a large number of electrically activated emittershaving different peak wavelengths are used—but such an arrangement maybe prohibitively expensive or impractical due to packaging constraintsand/or color mixing issues. Accordingly, in light emitting apparatusesaccording to certain embodiments, at least one of the first LEDcomponent and the second LED component preferably includes at least oneLED arranged to stimulate emissions of at least one lumiphoric material.In certain embodiments, a first LED component includes at least onefirst LED arranged to stimulate emissions of at least one firstlumiphoric material, and a second LED component includes at least onesecond LED arranged to stimulate emissions of at least one secondlumiphoric material.

As noted previously, combined emissions of a light emitting apparatuswhen operated in a first operating mode preferably embodies a colorrendering index (CRI) value of at least about 80 (more preferably avalue of at least about 85, still more preferably a value of at leastabout 90). When such a light emitting apparatus is operated in a secondoperating mode having increased emissions in the melatonin responsespectrum (thereby providing increasing msm/100 l values), the fractionof emissions in blue and/or cyan spectrum will increase relative tocolors characterized by longer wavelengths (e.g., green, yellow, red);accordingly, color rendering will typically decline. In certainembodiments, combined emissions of the first LED component and thesecond LED component when operated in the first operating mode embody aCRI value of preferably at least about 30 (more preferably at leastabout 40, more preferably at least about 50, still more preferably atleast about 60). Although CRI values as low as 30 may not be pleasingfor general illumination, such values may be acceptable for certainapplications, such as backlighting of (e.g., LCD) displays.

In certain embodiments, a light emitting apparatus as described hereinmay include at least one control circuit arranged to adjust supply ofcurrent to at least one of the first LED component and the second LEDcomponent to operate the first LED component and the second LEDcomponent according to the first operating mode or the second operatingmode.

In certain embodiments, one or more LED components of a light emittingapparatus as described herein may embody or be arranged in at least onesolid state emitter package.

A solid state emitter package may include at least one solid stateemitter chip (more preferably multiple solid state emitter chips) thatis enclosed with packaging elements to provide environmental protection,mechanical protection, color selection, and/or light focusing utility,as well as electrical leads, contacts, and/or traces enabling electricalconnection to an external circuit. One or more emitter chips may bearranged to stimulate one or more lumiphoric materials, which may becoated on, arranged over, or otherwise disposed in light receivingrelationship to one or more solid state emitters. A lens and/orencapsulant materials, optionally including lumiphoric material, may bedisposed over solid state emitters, lumiphoric materials, and/orlumiphor-containing layers in a solid state emitter package. Multiplesolid state emitters may be provided in a single package. In certainembodiments, multiple LED components as described herein may be providedin a single package. In other embodiments, one or more LED components asdescribed herein may include one or more LED packages. In certainembodiments, LED components are separately controllable. In certainembodiments, multiple LEDs within a LED component may be controlledindependently of one another.

In certain embodiments, a package including multiple solid stateemitters may include multiple die attach pads, with a single die attachpad supporting each separately controllable solid state emitter or eachseparately controllable group of solid state emitters. A packageincluding multiple solid state emitters may include a single lens (e.g.,a molded lens) arranged to transmit at least a portion of lightemanating from each solid state emitter. In certain embodiments, amolded lens may be arranged in direct contact with LED chips, die attachpads, other electrical elements, and/or exposed insulating materialalong a top surface of a substrate comprising insulating material. Incertain embodiments, a lens may be textured or faceted to improve lightextraction, and/or a lens may contain or have coated thereon variousmaterials such as lumiphors and/or scattering particles.

In certain embodiments, a light emitting apparatus including a first LEDcomponent and a second LED component as disclosed herein may include orbe embodied in one or more LED packages. One or more LED packages mayinclude one or more of the following features: a single leadframearranged to conduct electrical power to the first LED component and thesecond LED component; a single reflector arranged to reflect at least aportion of light emanating from each of the first LED component and thesecond LED component; a single submount supporting the first LEDcomponent and the second LED component; a single lens (e.g., a moldedlens) arranged to transmit at least a portion of light emanating fromeach of the first LED component and the second LED component; and asingle diffuser arranged to diffuse at least a portion of lightemanating from each of the first LED component and the second LEDcomponent.

In certain embodiments, a light emitting apparatus as disclosed herein(whether or not including one or more LED packages) may include at leastone of the following items arranged to receive light from multiple LEDcomponents: a single lens; a single optical element; a single diffuser;and a single reflector. In certain embodiments, a light emittingapparatus including multiple LED components may include at least one ofthe following items arranged to receive light from multiple LEDcomponents: multiple lenses; multiple optical elements; and multiplereflectors. Examples of optical elements include, but are not limited toelements arranged to affect light mixing, focusing, collimation,dispersion, and/or beam shaping.

In certain embodiments, a light emitting apparatus including first andsecond LED components may provide adjustable CCT output, and furtherprovide adjustable msm/100 l at different CCT values. For example, afirst and a second operating mode may correspond to a first target CCT,and a third and a fourth operating mode may correspond to a secondtarget CCT, wherein the second CCT differs from the first CCT by atleast about 300K, at least about 600K, at least about 1000K, or anysuitable value. The first and second operating modes provide msm/100 lvalues that differ from one another, and the third and fourth operatingmodes provide msm/100 l values that differ from one another. Suchmsm/100 l values differences are preferably at least about 10%, at leastabout 20%, at least about 30%, at least about 40%, at least about 50%,at least about 60%, at least about 80%, at least about 100%, at leastabout 125%, at least about 150%, at least about 200%, at least about300%, at least about 400% or any other suitable difference threshold.

If a LED component includes multiple electrically activated solid stateemitters (e.g., LEDs), then by adjusting operation of differentelectrically activated solid state emitters within the LED component,CCT output by the LED component may be altered. As noted previously,providing a cyan emitter (whether a cyan LED or a LED combined with acyan lumiphor) in a LED component together with another electricallyactivated solid state emitter may beneficially permit color temperatureto be varied over a color temperature range of less than 3000K to about4000K, since the tie line for a cyan solid state emitter having a ˜487nm peak wavelength is substantially parallel to the blackbody locus fora color temperature of less than 3000K to about 4000K. Accordingly, withappropriate selection of supplemental emitters for use in amulti-emitter LED component, it is straightforward to adjust CCT of theLED component. When using first and second multi-emitter LED components,each LED component may have adjustable CCT, but when both LED componentsare arranged to operate at a common CCT value, a msm/100 l value oftheir combined emissions may be adjusted by adjusting total currentsupplied to the first LED component relative to the second LEDcomponent. In this manner, a light emitting apparatus may provideadjustable CCT output, and further provide adjustable msm/100 l atdifferent CCT values.

In one embodiment, a first LED component and a second LED component arearranged to be operated at or near a first target correlated colortemperature in a first operating mode in which combined emissions of thefirst LED component and the second LED component (i) are within fourMacAdam ellipses of the first target correlated color temperature, and(ii) embody a first melatonin suppression milliwatt per hundred lumensvalue; wherein the first LED component and the second LED component arearranged to be operated at or near the first target correlated colortemperature in a second operating mode in which combined emissions ofthe first LED component and the second LED component (i) are within fourMacAdam ellipses of the first target correlated color temperature, and(ii) embody a second melatonin suppression per hundred lumens value thatis at least about 10 percent greater than the first melatoninsuppression per hundred lumens value; wherein the first LED componentand the second LED component are arranged to be operated at or near asecond target correlated color temperature in a third operating mode inwhich combined emissions of the first LED component and the second LEDcomponent (i) are within four MacAdam ellipses of the second targetcorrelated color temperature, and (ii) embody a third melatoninsuppression milliwatt per hundred lumens value; wherein the first LEDcomponent and the second LED component are arranged to be operated at ornear the second target correlated color temperature in a fourthoperating mode in which combined emissions of the first LED componentand the second LED component (i) are within four MacAdam ellipses of thesecond target correlated color temperature, and (ii) embody a fourthmelatonin suppression per hundred lumens value that is at least about 10percent greater than the third melatonin suppression per hundred lumensvalue; and wherein the second target correlated color temperaturediffers from the first correlated color temperature preferably by atleast about 300K (more preferably by at least about 600K, still morepreferably by at least about 1000K). Preferably, each of the first LEDcomponent and the second LED component in such embodiment includesmultiple electrically activated emitters (e.g., LEDs), optionallyarranged to stimulate at least one lumiphoric material.

In certain embodiments, combined emissions of the first LED componentand the second LED component when operated in at least one of the firstoperating mode and the third operating mode (or when operated in each ofthe first and second operating modes, at different times) embody a colorrendering index (CRI) value of at least about 80. In such embodiments,combined emissions of the first LED component and the second LEDcomponent when operated in at least one of the second operating mode andthe fourth operating mode (or whether operated in each of the second andfourth operating modes, at different times) may embody a color renderingindex (CRI) value of at least about 30.

As noted previously, providing multiple LED components having differentmelatonin suppression characteristics in a single lighting device orapparatus wherein the LED may be separately controlled permitsaggregated melatonin suppression characteristics of a lighting device tobe adjusted. In certain embodiments, adjustment of melatonin suppressioncharacteristics may be accompanied by small or minimal change incorrected color temperature (e.g., each having a CCT within a specifiednumber of MacAdam ellipses of a target CCT as disclosed herein). Incertain embodiments, a light emitting apparatus may provide adjustableCCT output, and further provide adjustable msm/100 l at different CCTvalues.

In certain embodiments, a backlight is arranged to illuminate a displaypanel arranged to display at least one of images and text, wherein thebacklight includes a first LED component; a second LED component; and atimer or clock arranged to trigger switching between a first operatingmode and a second operating mode; wherein in the first operating modethe first LED component and second LED component generate combinedemissions that (i) are within four MacAdam ellipses of a targetcorrelated color temperature, and (ii) embody a first msm/100 l value;and wherein in the second operating mode the first LED component andsecond LED component generate combined emissions that (i) are withinfour MacAdam ellipses of the target correlated color temperature, and(ii) embody a second msm/100 l value that is at least about 10 percentgreater than the first msm/100 l value.

One advantage of providing a backlight having an associated timer (e.g.,a user-adjustable timer apparatus) or clock arranged to triggerswitching between operating modes having different msm/100 l values isthat it permits a user to define a time period for maintaining a desiredmelatonin suppressing effect. For example, a user of an electronicreader or tablet computer may desire to read for a specified period(e.g., one hour) before sleeping but the user does not wish to remainawake substantially longer than the specified period. Such a user mightset a timer associated with a backlight of the electronic reader ortablet computer to maintain a high msm/100 l value according to oneoperating mode for a defined period, such that at the end of thepredefined period the timer will trigger the backlight to operateaccording to another operating mode having a reduced msm/100 l value topermit the user to start releasing melatonin and thereby permit the userto fall asleep.

Various illustrative features are described below in connection with theaccompanying figures.

FIG. 7A is a table identifying lumens, total lumens, relative lumens,CRI, and msm/100 l versus CRI at a CCT of 3000K obtained by modelingcombined output of a first LED component including a blue LED arrangedto stimulate emissions of a yellow phosphor (i.e., a BSY component) anda second LED component including a cyan LED arranged to stimulateemissions of a red phosphor (i.e., a CSR component). FIG. 7B is plot ofmsm/100 l versus CRI at a CCT of 3000K using data listed in the table ofFIG. 7A. As shown in FIGS. 7A-7B, maximum msm/100 l values are obtainedby operating the second LED component exclusively while zero lumens areoutput by the first LED component, but the CRI value is extremely low(−22.6). As a greater proportion of lumens are output by the first (BSY)component, CRI values steadily improve (to an ultimate value of 94.1),but msm/100 l values decline (to an ultimate value of 51).

For purposes of general illumination typically requiring CRI of at leastabout 80, the potential operating modes depicted in the last three rowsof FIG. 7A all provide CRI values exceeding 80, and with msm/100 lvalues ranging from 51 to 56 (representing an increase of 9.8 percentgoing from a msm/100 l value of 51 to 56). This demonstrates that aroughly 10% increase in msm/100 l can be obtained by operating two LEDcomponents (e.g., BSY and CSR components) according to different modesat a constant CCT of 3000K while maintaining CRI above 80.

For other purposes where color rendering may not be as critical (e.g.,backlighting), comparison of the fourth and last lines of FIG. 7Ademonstrates that msm/100 l may be increased from a value of 51 (with aCRI value of 94.1) to a value of 72.4 (with a CRI value of 35.1). Thisdemonstrates that a roughly 42% increase in msm/100 l can be obtained byoperating two LED components (i.e., the specified BSY and CSRcomponents) according to different operating modes at a constant CCT of3000K while maintaining CRI above 30.

FIG. 8A is a table identifying lumens, total lumens, relative lumens,CRI, and msm/100 l versus CRI at a CCT of 5000K obtained by modelingcombined output of a first LED component including a blue LED arrangedto stimulate emissions of a yellow phosphor (i.e., a BSY component) anda second LED component including a cyan LED arranged to stimulateemissions of a red phosphor (i.e., a CSR component). FIG. 8B is plot ofmsm/100 l versus CRI at a CCT of 3000K using data listed in the table ofFIG. 8A. As shown in FIGS. 8A-8B, the maximum msm/100 l value (140.3) isobtained by operating the second LED component exclusively while zerolumens are output by the first LED component, but the CRI value isextremely low (−44.5). As a greater proportion of lumens are output bythe first (BSY) component, CRI values steadily improve (to an ultimatevalue of 95.7), but msm/100 l values decline (to an ultimate value of90.7).

For purposes of general illumination typically requiring CRI of at leastabout 80, the potential operating modes depicted in the last three rowsof FIG. 8A all provide CRI values exceeding 80, and with msm/100 lvalues ranging from 90.7 to 96 (representing an increase of 5.8 percentgoing from a msm/100 l value of 90.7 to 96). This demonstrates that aroughly 6% increase in msm/100 l can be obtained by operating two LEDcomponents (e.g., BSY and CSR components) according to different modesat a constant CCT of 5000K while maintaining CRI above 80.

For other purposes where color rendering may not be as critical (e.g.,backlighting), comparison of the fourth and last lines of FIG. 8Ademonstrates that msm/100 l may be increased from a value of 90.7 (witha CRI value of 95.7) to a value of 110.1 (with a CRI value of 40.2).This demonstrates that a roughly 34% increase in msm/100 l can beobtained by operating two LED components (i.e., the specified BSY andCSR components) according to different operating modes at a constant CCTof 5000K while maintaining CRI above 30.

FIG. 9A is a table identifying u′, v′ coordinates, CRI, R9, andmelatonin suppressing milliwatts per 100 lumens values at a CCT of 5000Kfor a first reference point on the blackbody locus, a second referencepoint to the right of the blackbody locus, and a third reference pointto the left of the blackbody locus. FIG. 9B is a plot of the u′, v′values for the three reference points identified in FIG. 9A superimposedon a 1976 CIE chromaticity diagram. The second and third referencepoints shown in FIG. 9B represent potential operating points of twoseparate LED components. If such LED components were provided in asingle light emitting apparatus, then proportion of electric current maybe adjusted to the components to provide a combined output embodying anypoint along an imaginary line from the second reference point (throughthe first reference point) to the third reference point. As shown inFIG. 9A, the second (right) reference point embodies a CRI of 79 and amsm/100 l value of 106.1, whereas the third (left) reference pointembodies a CRI of 71 and a msm/100 l value of 93.5, and the firstreference point embodies a CRI of 79 and a msm/100 l value of 106.1.Although FIGS. 9A-9B depict reference points at a CCT of 5000K, similarrelationships are expected for combinations of emitters arranged to beoperated at other CCT values.

As noted previously, in different embodiments, individual LED componentsof a solid state emitter apparatus may be arranged on differentsubstrates, or multiple LED components may be arranged in or on a singlesubstrate. In certain embodiments, multiple LED components as describedherein may be arranged in a single solid state emitter package.

FIG. 10A illustrates a solid state emitter package 100 that may embodyor include one or more LED components as described herein. The emitterpackage 100 includes multiple (e.g., four) LED chips 150A-150D that maybe separately controlled and that are supported by an insulatingsubstrate 110 (e.g., preferably, but not necessarily. comprising ceramicmaterial) having an upper surface 111, a lower surface 112, and sidewalls 113-116 extending between the upper surface 111 and the lowersurface 112. Electrical traces 140 are arranged over the substrate 110,including multiple die attach pads 141A-141D and additional electricalelements 142A-142D arranged proximate to the die attach pads 141A-141D.Where the die attach pads 141A-141D are electrically conductive, the LEDchips 150A-150D may be arranged with bottom side contacts thereof inelectrical communication with the die attach pads 141A-141D, and withtop side contacts thereof in electrical communication with theelectrical elements 142A-142D by way of wirebonds 152. The die attachpads 141A-141D and electrical elements 142A-142D may comprise one ormore metals patterned on (or in) the top surface 111 of the substrate110. Gaps 145 may be provided between adjacent die attach pads 141A-141Dand/or electrical elements 142A-142D to prevent undesired conductiveelectrical communication. In certain embodiments, die attach pads neednot be electrically conductive, such as in cases where anode and cathodeconnections to a solid state emitter chip are both made with wirebonds.Optional elements that may be formed concurrently with the electricaltraces 140 but not serve as part of any conductive path through thepackage 100 include a polarity or positional identifying mark 148 andchip singulation alignment marks 149-1, 149-2 (used during singulation,such as by sawing, of emitter packages or subassemblies thereof from awafer or superassembly from which multiple emitter packages are formed).An insulating soldermask 147 (shown in greater detail in FIG. 10B) ispatterned over peripheral portions of the electrical traces 140, and amolded lens 160 (e.g., including a raised or hemispherical portion 161and a base portion 162) is arranged over the top surface 111 of thesubstrate 110 and is arranged to transmit at least a portion of lightgenerated by the emitter chips 150A-150D.

LED chips 150A-150D of any suitable peak wavelength (e.g., color) may beused, and optionally arranged to stimulate emissions of one or morelumiphors (e.g., phosphors). Although the LED chips 150A-150D may beseparately controlled, in certain embodiments groups of two or more LEDchips 150A-150D or groups of LED chips may be controlled together in agroupwise fashion. As noted previously, the package 100 may embody oneor more LED components, with each LED component comprising at least oneLED chip 150A-150D (optionally multiple LED chips), with one or more LEDchips 150A-150D optionally arranged to stimulate emissions of one ormore lumiphoric materials. In certain embodiments, the solid stateemitter package 100 may include two LED components, with each LEDcomponent including two LED chips 150A-150D. In certain embodiments, thesolid state emitter package 100 may include one, two, three, or four LEDcomponents. Although four LED chips 150A-150D are illustrated in FIG.10A, it is to be appreciated that a LED package may include anydesirable number of LED chips, including groups of chips arranged inseries, in parallel, or in series-parallel configurations.

FIG. 10B is a top plan view of a first subassembly 100-3 of the emitterpackage 100 illustrated in FIG. 10A, with the subassembly 100-3 lackingthe lens 160 and representing the solder mask 147 with hatched lines foremphasis. As shown in FIG. 10B, the solder mask 147 is arranged overperipheral portions of the top side electrical traces 140 between thesubstrate edges 113-116 and a roughly circular window arranged below araised portion 161 of the lens 160.

FIG. 100 is a top plan view of a second subassembly 100-1 of the emitterpackage 100 illustrated in FIG. 10A, with the subassembly 100-1 lackinga lens, solder mask, and LEDs, but with the traces 140 represented withhatched lines for emphasis. As shown in FIG. 100, the electrical traces140 extend peripherally outward beyond the roughly circular windowdefined in the solider mask 147 (illustrated in FIG. 10B), with optionalalignment holes 143A-143D defined in peripheral portions of the dieattach pads 141A-141D, and optional alignment holes 144A-144D defined inperipheral portions of the additional electrical elements 142A-142D. Thevarious alignment holes 143A-143D, 144A-144D may be used duringmanufacture, for example, to promote alignment with electricallyconductive vias (e.g., as shown in FIG. 10G) defined through theinsulating substrate 110.

FIG. 10D is a top plan view of a third subassembly 100-2 of the emitterpackage 100 illustrated in FIG. 10A, with the subassembly 100-2 lackinga lens, and LEDs, but with the solder mask 147 represented with hatchedlines for emphasis

FIG. 10E is a bottom plan view of each of the emitter package 100 ofFIG. 10A and the subassemblies of FIGS. 1B, 1C, and 1D. A bottom surface112 of the substrate includes four anodes 121A-121D and four cathodes122A-122D patterned thereon (e.g., as electrical traces), with onepaired anode/cathode per quadrant. The separate anodes 121A-121D andcathodes 122A-122D enable separate control of the multiple LED chips150A-150B if desired. Each anode 121A-121D may include an optionalalignment hole 123A-123D and each cathode 122A-122D may include anoptional alignment hole 124A-124D. The various anodes 121A-121D andcathodes 122A-122D are separated by gaps that may be filled with soldermask material sections 127-1, 127-2. A thermal element (e.g., thermalspreading element) 126 may be arranged along the bottom surface 112between the solder mask material sections 127-1, 127-2 and generallyunderlapping the solid state emitters 150A-150D. The thickness of thethermal element 126 may be the same as or different from (e.g., thickerthan) the anodes 121A-121D and cathodes 122A-122D. As show, the device100 is devoid of any anode or cathode arranged on, or extendinglaterally beyond, any side wall 113-116 of the LED device 100.

FIG. 10F is a right side elevation view of the first subassembly 100-3illustrated FIG. 10B, being devoid of a lens but showing solid stateemitter chips 150B, 150D and wirebonds 152 arranged over a top surface111 of the substrate 110.

FIG. 10G is a side cross-sectional view of the third subassembly 100-2of FIG. 10D, taken along section lines “A”-“A” depicted in FIG. 10E.FIG. 10G illustrates electrically vias 125C, 125D defined through thesubstrate 110 between the top and bottom surfaces 111, 112, and arrangedto provide electrical communication between top side traces (die attachpads) 141C, 14D and bottom side traces (anodes) 121C, 121D. The thermalelement 112 is further illustrated along the bottom surface 112 of thesubstrate 110. As shown in FIG. 10G, the upper solder mask 147 mayextend laterally past the top side traces 140 but not quite to sideedges 113, 115 of the substrate 110.

FIG. 10H is an exploded right side elevation view of the emitter package100, separately depicting the lens 160 registered with the firstsubassembly 100-3 of FIG. 10B. FIG. 10I is another perspective view ofthe emitter package 100. Although FIGS. 10H-10I illustrate the lens 160as including a hemispherical central raised portion 161, it is to beappreciated that any suitable lens shape (including raised, flat, orrecessed shapes) may be provided in various embodiments. The lens 160 ispreferably molded and may either be molded in place over the emitterchips 150A-150D and substrate 110, or may be pre-molded and then affixedto a subassembly including the substrate 110 and emitter chips150A-150D.

FIG. 11A illustrates a lighting apparatus 1100 including first andsecond LED components 1101, 1102 supported in or on a substrate or otherbody structure 1109. The first and the second LED components 1101, 1102each include at least one LED chip (optionally multiple LED chips1103A-1103B, 1104A-1104B). In certain embodiments, at least one LED chip1103A-1103B, 1104A-1104B of each LED component 1101, 1102 is preferablyarranged to stimulate emissions of one or more lumiphoric materials1105A, 1106A. Although FIG. 11A illustrates two LED chips 1103A-1103B,1104A-1104B as being associated with each LED component 1101, 1102, itis to be appreciated that any suitable number of one or more (e.g., one,two, three, four, five, six, etc.) LED chips may be associated with oneor more LED components in certain embodiments. The first and second LEDcomponents 1101, 1102 may embody any suitable LED components, features,and/or capabilities as described herein, and are preferably separatelycontrollable (e.g., in order to adjust melatonin suppressioncharacteristics of combined emissions of the lighting apparatus 1100).In certain embodiments, each LED within a single LED component may beindividually controlled, or groups of two or more LEDs within a singlecomponent may be controlled as a group.

FIG. 11B illustrates a lighting apparatus 1110 including first andsecond LED components 1111, 1112 supported in or on a substrate or otherbody structure 1119. The first LED component 1111 includes a first(e.g., cyan) LED 1113A arranged to stimulate emissions of at least onefirst (e.g., red) lumiphoric material 1115A, and the second LEDcomponent 1112 includes a second (e.g., blue) LED 1114A arranged tostimulate emissions of at least one second (e.g., yellow) lumiphoricmaterial 1116A. The first and second LED components 1111, 1112 mayembody any suitable LED components, features, and/or capabilities asdescribed herein, and are preferably separately controllable (e.g., inorder to adjust melatonin suppression characteristics of combinedemissions of the lighting apparatus 1110). In certain embodiments,additional or different LEDs and/or lumiphors may be associated with oneor more of the LED components 1111, 1112, and/or one or more additionalLED components may be provided.

FIG. 11C illustrates a lighting apparatus 1120 including first andsecond LED components 1121, 1122 supported in or on a substrate or otherbody structure 1129. The first LED component 1121 includes a first(e.g., cyan) LED 1123A arranged to stimulate emissions of at least onefirst (e.g., yellow) lumiphoric material 1125A, and the second LEDcomponent 1122 includes a second (e.g., blue) LED 1124A arranged tostimulate emissions of at least one second (e.g., red) lumiphoricmaterial 1126A. The first and second LED components 1121, 1122 mayembody any suitable LED components, features, and/or capabilities asdescribed herein, and are preferably separately controllable (e.g., inorder to adjust melatonin suppression characteristics of combinedemissions of the lighting apparatus 1120). In certain embodiments,additional or different LEDs and/or lumiphors may be associated with oneor more of the LED components 1121, 1122, and/or one or more additionalLED components may be provided.

FIG. 11D illustrates a lighting apparatus 1130 including first andsecond LED components 1131, 1132 supported in or on a substrate or otherbody structure 1139. The first LED component 1131 includes a first(e.g., blue) LED 1133A arranged to stimulate emissions of at least onefirst (e.g., yellow) lumiphoric material 1135A, and the second LEDcomponent 1132 includes a second (e.g., green) LED 1134A arranged tostimulate emissions of at least one second (e.g., red) lumiphoricmaterial 1136A. The first and second LED components 1131, 1132 mayembody any suitable LED components, features, and/or capabilities asdescribed herein, and are preferably separately controllable (e.g., inorder to adjust melatonin suppression characteristics of combinedemissions of the lighting apparatus 1130). In certain embodiments,additional or different LEDs and/or lumiphors may be associated with oneor more of the LED components 1131, 1132, and/or one or more additionalLED components may be provided.

FIG. 11E illustrates a lighting apparatus 1140 including first andsecond LED components 1141, 1142 supported in or on a substrate or otherbody structure 1149. The first LED component 1141 includes a first(e.g., blue) LED 1143A arranged to stimulate emissions of at least onefirst (e.g., yellow) lumiphoric material 1145A. The second LED component1142 includes a second (e.g., blue) LED 1144A arranged to stimulateemissions of at least one second (e.g., yellow) lumiphoric material1146A. Preferably, the peak wavelength and/or full-width half-maxcharacteristics differ significantly between the first and second LEDs1143A, 1144A, and/or between the first and second lumiphoric materials1145A, 1146A, in order to confer different melatonin suppressioncharacteristics. For example, the peak wavelengths of the first andsecond LEDs (or of the first and second lumiphoric materials 1145A,1146A) may differ by threshold values of at least about 10 nm, at leastabout 20 nm, at least about 30 nm or some other suitable value; and FWHMvalues of the first and second LEDs (or of the first and secondlumiphoric materials 1145A, 1146A) may differ by 10%, 20%, 30%, or someother suitable value. The first and second LED components 1141, 1142 mayembody any suitable LED components, features, and/or capabilities asdescribed herein, and are preferably separately controllable (e.g., inorder to adjust melatonin suppression characteristics of combinedemissions of the lighting apparatus 1140). In certain embodiments,additional or different LEDs and/or lumiphors may be associated with oneor more of the LED components 1141, 1142, and/or one or more additionalLED components may be provided.

FIG. 11F illustrates a lighting apparatus 1150 similar to that describedabove in connection with FIG. 11E, with the addition of multiple (e.g.,yellow and red) lumiphoric materials to each solid state emitter. Theapparatus 1150 includes first and second LED components 1151, 1152supported in or on a substrate or other body structure 1159. The firstLED component 1151 includes a first (e.g., blue) LED 1153A arranged tostimulate emissions of multiple first (e.g., yellow and red) lumiphoricmaterials 1155A. The second LED component 1152 includes a second (e.g.,blue) LED 1154A arranged to stimulate emissions multiple second (e.g.,yellow and red) lumiphoric materials 1156A. Preferably, the peakwavelength and/or full-width half-max characteristics differsignificantly between the first and second LEDs 1153A, 1154A, and/orbetween corresponding components of the first and second lumiphoricmaterials 1155A, 1156A, in order to confer different melatoninsuppression characteristics. The first and second LED components 1151,1152 may embody any suitable LED components, features, and/orcapabilities as described herein, and are preferably separatelycontrollable (e.g., in order to adjust melatonin suppressioncharacteristics of combined emissions of the lighting apparatus 1150).In certain embodiments, additional or different LEDs and/or lumiphorsmay be associated with one or more of the LED components 1151, 1152,and/or one or more additional LED components may be provided

FIG. 11G illustrates a lighting apparatus 1160 including first andsecond LED components 1161, 1162 supported in or on a substrate or otherbody structure 1169. The first LED component 1161 includes a first(e.g., blue) LED 1163A arranged to stimulate emissions of at least onefirst (e.g., cyan) lumiphoric material 1165A, in combination with anadditional (e.g., red) LED 1163B. The second LED component 1162 includesa second (e.g., blue) LED 1164A arranged to stimulate emissions of atleast one second (e.g., yellow) lumiphoric material 1166A. The first andsecond LED components 1161, 1162 may embody any suitable LED components,features, and/or capabilities as described herein, and are preferablyseparately controllable (e.g., in order to adjust melatonin suppressioncharacteristics of combined emissions of the lighting apparatus 1160).In certain embodiments, additional or different LEDs and/or lumiphorsmay be associated with one or more of the LED components 1161, 1162,and/or one or more additional LED components may be provided.

FIG. 11H illustrates a lighting apparatus 1170 including first andsecond LED components 1171, 1172 supported in or on a substrate or otherbody structure 1179. The first LED component 1171 includes a first(e.g., blue) LED 1173A arranged to stimulate emissions of at least onefirst (e.g., cyan) lumiphoric material 1175A, in combination with anadditional (e.g., green) LED 1173B arranged to stimulate emissions of atleast one additional (e.g., red) lumiphoric material 1175B. The secondLED component 1172 includes a second (e.g., blue) LED 1174A arranged tostimulate emissions of at least one second (e.g., yellow) lumiphoricmaterial 1176A. The first and second LED components 1171, 1172 mayembody any suitable LED components, features, and/or capabilities asdescribed herein, and are preferably separately controllable (e.g., inorder to adjust melatonin suppression characteristics of combinedemissions of the lighting apparatus 1160). In certain embodiments,additional or different LEDs and/or lumiphors may be associated with oneor more of the LED components 1171, 1172, and/or one or more additionalLED components may be provided.

Although the FIGS. 11A-11H illustrate use of LEDs having peakwavelengths in the visible range, it is to be appreciated that LEDshaving peak wavelengths in a non-visible range (e.g., ultraviolet LEDs)may be substituted, in combination with appropriate lumiphors to providedesired spectral output characteristics.

FIG. 12 illustrates interconnections between various components of alight emitting apparatus 1200 including first and second LED components1201, 1202 arranged in series, with at least one control circuit 1210arranged to control modulation of current and/or duty cycle of the LEDcomponents 1201, 1202 using controllable bypass and/or shunt elements1211, 1212. The at least one control circuit 1210 may be controlledresponsive to one or more user input elements 1206, one or more timer orclock elements 1207, and/or one or more sensor elements 1208 (e.g.,temperature sensing element, photosensors, etc.). Various components ofthe light emitting apparatus 1200 may be supported by, arranged on, orarranged in electrical communication portions of a substrate or supportelement 1209. In operation, current is applied to the lighting apparatus1200 between anode 1221A and cathode 1221B. Supply of current to, and/orduty cycle of, a first LED component 1201 may be controlled with a firstcontrollable bypass or shunt element 1211. Similarly, supply of currentto, and/or duty cycle of, a second LED component 1202 may be controlledwith a second controllable bypass or shunt element 1212, with the secondLED component 1202 arranged in series with the first LED component 1201.Each of the first and second controllable bypass or shunt elements 1211,1212 may be controlled by at least one control circuit 1210, optionallyin response one or more user input elements 1206, one or more timer orclock elements 1207, and/or one or more sensor elements 1208.

FIG. 13 illustrates interconnections between various components of alight emitting apparatus 1300 including first and second LED components1301, 1302 arranged in parallel, with at least one control circuit 1310(e.g., optionally including control circuit portions 1310A, 1310B)arranged to control modulation of current and/or duty cycle of the LEDcomponents 1301, 1302 using controllable bypass and/or shunt elements1311, 1312. The at least one control circuit 1310 may be controlledresponsive to one or more user input elements 1306, one or more timer orclock elements 1307, and/or one or more sensor elements 1308. Variouscomponents of the light emitting apparatus 1300 may be supported by,arranged on, or arranged in electrical communication portions of asubstrate or support element 1309. In operation, current may be suppliedto the first LED component 1301 via a first anode 1321A and cathode1321B, wherein supply of current to, and/or duty cycle of, the first LEDcomponent 1301 may be modulated with a first controllable bypass orshunt element 1311. In a like manner, current may be supplied to thesecond LED component 1302 via a second anode 1322A and cathode 1322B,wherein supply of current to, and/or duty cycle of, the second LEDcomponent 1302 may be modulated with a second controllable bypass orshunt element 1312. The first and second controllable bypass or shuntelements 1311, 1312 may be controlled by at least one control circuit1310 (optionally with dedicated circuit portions 1310A, 1310B),optionally in response one or more user input elements 1306, one or moretimer or clock elements 1307, and/or one or more sensor elements 1308.

FIG. 14 illustrates a lighting apparatus (e.g., light fixture) 1410according to at least one embodiment. The apparatus 1400 includes asubstrate or mounting plate 1475 to which multiple solid state emitter(e.g., LED) lamps 1470-1 to 1470-6 (with at least some lamps 1470-1 to1470-6 optionally embodying a multi-chip lamp such as a multi-chip LEDpackage) are attached, wherein each lamp 1470-1 to 1470-6 embodies atleast on LED component as described herein. Although the mounting plate1475 is illustrated as having a circular shape, the mounting plate maybe provided in any suitable shape or configuration (including non-planarand curvilinear configurations). Different solid state emitter chipswithin a single multi-chip solid state emitter lamp may be configured toemit the same or different colors (e.g., wavelengths) of light. Withspecific reference to a first solid state lamp 1470-1, each solid statelamp 1470-1 to 1470-6 may include multiple solid state emitters (e.g.,LEDs) 1474A-1474C preferably arranged on a single submount 1461.Although FIG. 14 illustrates four solid state emitter chips as beingassociated with each multi-chip solid state lamp 1470-1 to 1470-6, it isto be appreciated that any suitable number of solid state emitter chipsmay be associated with each multi-chip solid state lamp 1470-1 to1470-6, and the number of solid state emitter chips associated withdifferent (e.g., multi-chip) solid state lamps may be different. Eachsolid state lamp in a single fixture 1410 may be substantially identicalto one another, or solid state lamps with different outputcharacteristics may be intentionally provided in a single fixture 1410.

The solid state lamps 1470-1 to 1470-6 may be grouped on the mountingplate 1475 in clusters or other arrangements so that the light fixture1410 outputs a desired pattern of light. In certain embodiments, atleast one state emitter lamp associated with a single fixture 1410includes a lumiphor-converted light emitting component (e.g., BSY, BSC,BS(Y+R), CSR, CSY, GSR, UVSC, etc. emitter). In certain embodiments,multiple LED components having different melatonin suppression effectsin the apparatus 1410 may be separately controlled separately, to permitaggregated melatonin suppression effect of the lighting device to beadjusted, preferably wherein such adjustment of melatonin suppressioneffect may be accompanied by small or minimal change in corrected colortemperature.

With continued reference to FIG. 14, the light fixture 1410 may includeone or more control circuit components 1480 arranged to operate thelamps 1470-1 to 1470-6 by independently applying currents and/oradjusting duty cycle of respective LED components. In certainembodiments, individual solid state chip 1464A-1464D in various lamps1470-1 to 1470-6 may be configured to be individually addressed by thecontrol circuit 1480. In certain embodiments, the lighting apparatus1410 may be self-ballasted. In certain embodiments, a control circuit1480 may include a current supply circuit configured to independentlyapply an on-state drive current to each individual solid state chipresponsive to a control signal, and may include one or more controlelements configured to selectively provide control signals to thecurrent supply circuit. As solid state emitters (e.g., LEDs) arecurrent-controlled devices, the intensity of the light emitted from anelectrically activated solid state emitter (e.g., LED) is related to theamount of current with which the device is driven. A common method forcontrolling the current driven through an LED to achieve desiredintensity and/or color mixing is a Pulse Width Modulation (PWM) scheme,which alternately pulses the LEDs to a full current “ON” state followedby a zero current “OFF” state. The control circuit 1480 may beconfigured to control the current driven through the solid state emitterchips 1464A-1464D associated with the lamps 1470-1 to 1470-6 using oneor more control schemes known in the art. The control circuit 1480 maybe attached to an opposite or back surface of the mounting plate 1475,or may be provided in an enclosure or other structure (not shown) thatis segregated from the lighting device 1400.

While not illustrated in FIG. 14, the light fixture 1410 a may furtherinclude one or more heat spreading components and/or heatsinks forspreading and/or removing heat emitted by solid state emitter chips1464A-1464D associated with the lamps 1470-1 to 1470-6. For example, aheat spreading component may include a sheet of thermally conductivematerial configured to conduct heat generated by the solid state emitterchips 1464A-1464D of the light fixture 1410 and spread the conductedheat over the area of the mounting plate 1475 to reduce thermalstratification in the light fixture 1410. A heat spreading component maybe embodied in a solid material, a honeycomb or other mesh material, ananisotropic thermally conductive material (e.g., graphite), one or morefins, and/or other materials or configurations.

FIG. 15 illustrates a lighting apparatus (e.g., light fixture) 1510according to at least one embodiment. The apparatus includes multiplesolid state emitter lamps 1500A-1500X (which may optionally be embodiedin solid state emitter packages) each including multiple solid statelight emitting chips (e.g., LEDs) 1548A-1548X—with each lamp 1500A-1500Xembodying one or more LED components as described previously herein.Each lamp 1500A-1500X preferably includes multiple emitters arranged togenerate spectral output including different peak wavelengths. (Althoughsix lamps 1500A-1500X are shown, it is to be appreciated that anydesirable number of clusters may be provided, as represented by thevariable “X”). In certain embodiments, each lamp 1500A-1500X may embodyan individually temperature compensated lamp. Each lamp 1500A-1500X maypreferably (but not necessarily) include a single submount 1542A-1542Xto which the multiple LEDs 1548A-1548X are mounted or otherwisesupported. The lighting device 1510 includes a body structure orsubstrate 1511 to which each lamp 1500A-1500X may be mounted, with eachcluster 1500A-1500X optionally being arranged in conductive thermalcommunication with a single heatsink 1518 and further arranged to emitlight to be diffused by a single diffuser or other optical element 1517.The lighting device 1510 is preferably self-ballasted. Power may besupplied to the lighting device via contacts 1516 (e.g., as may beembodied in a single anode and single cathode, or multiple anodes andcathodes). A power conditioning circuit 1512 may provide AC/DCconversion utility, voltage conversion, and/or filtering utility. Atleast control circuit 1514 may be provided to control operation (e.g.,control dimming) of one or more lamps 1500A-1500X or subgroups thereof.In certain embodiments, each lamp 1500A-1500X may include one or moreemitters of a first LED component and one or more emitters of a secondLED component. In other embodiments, each lamp 1500A-1500X may includeemitters of either a first LED component or a second LED component, butnot emitters of both LED components within the same specific lamp1500A-1500X. In one or more photosensors or light sensing elements (notshown) may be arranged to receive emissions from one or more clusters1500A-1500X, with an output signal of the one or more light sensingelements being used to control or adjust operation of the clusters1500A-1500X, such as to ensure attainment of a desired output color oroutput color temperature by the clusters 1500A-1500X. In certainembodiments, multiple LED components having melatonin suppressioncharacteristics in the apparatus 1510 may be separately controlledseparately, to permit melatonin suppression effect of the lightingdevice to be adjusted, preferably wherein such adjustment of melatoninsuppression effect may be accompanied by small or minimal change incorrected color temperature.

In certain embodiments, two or more solid state emitter (e.g., LED)components as described herein may be embodied in backlights for displaypanels. Various embodiments including backlights are illustrated inFIGS. 16-18.

FIG. 16 is a perspective assembly view of a display device 1600including a substrate 1601 supporting multiple solid state emittingelements 1604A-1604X constituting a backlight illuminate (e.g., directlybacklight) a display (e.g., LCD) panel 1609, such as may be arranged todisplay text, images, and/or graphics. (Although FIG. 16 shows thedisplay device 1600 having thirty-two solid state light emitters, itwill be readily apparent to one skilled in the art that any suitablenumber of emitters may be provided. For this reason, the designation “X”is used to represent the last element in a series, with theunderstanding that the suffix “X” in such context represents a variablethat could represent any desired number of elements.) In certainembodiments, each light emitting element 1604A-1604X comprises a firstor a second LED component as described herein, arranged to have the sameor similar chromaticities but being controllable to permit adjustment ofmelatonin suppression effects. In certain embodiments, each lightemitting element 1604A-1604X comprises a first and a second LEDcomponent as outlined above. In certain embodiments, each solid statelight emitting element 1604A-1604X comprises a multi-chip solid stateemitter package. Multiple emitters in a multi-chip solid state emitterpackage (and multiple LED within a LED component) may be independentlycontrolled. In certain embodiments, individual solid state emittingelements or groups of solid state emitting elements 1604A-1604X may beindependently controlled with respect to at least one of melatoninsuppression characteristics, intensity, color, and color temperature.Independent control of different solid state emitter elements1604A-1604X may be used to provide local dimming and/or localcoloring/color enhancement.

FIG. 17 is a perspective assembly view of a display device 1700including a backlight waveguide 1711 arranged to be lit along edgesthereof by multiple solid state light emitting elements 1704A-1704X,1705A-1705X as described herein, with the backlight waveguide 1711arranged to illuminate (e.g., backlight) a display panel such as a LCDpanel. Although FIG. 17 illustrates only two edges of the waveguide 1711as having associated light emitting elements 1704A-1704X, 1705A-1705X,it is to be understood that all four edges of the waveguide 1711 mayhave associated solid state light emitting components. In certainembodiments, each light emitting element 1704A-1704X, 1705A-1705Xcomprises a first or a second LED component as described herein, whichhave the same or similar chromaticities but are controllable to permitadjustment of melatonin suppression effects. In certain embodiments,each light emitting element 1704A-1704X, 1705A-1705X comprises a firstand a second LED component as outlined above. In certain embodiments,each solid state light emitting element 1704A-1704X, 1705A-1705Xcomprises a multi-chip solid state emitter package. Multiple emitters ina multi-chip solid state emitter package (and multiple LED within a LEDcomponent) may be independently controlled. In certain embodiments,individual solid state emitting elements or groups of solid stateemitting elements 1704A-1704X, 1705A-1705X may be independentlycontrolled with respect to at least one of melatonin suppressioncharacteristics, intensity, color, and color temperature. Independentcontrol of different solid state emitter elements 1704A-1704X,1705A-1705X may be used to provide local dimming and/or localcoloring/color enhancement.

FIG. 18 is a schematic view of a light emitting group or array 1800including solid state emitter (e.g., LED) components 1801A-1801X asdescribed herein, optionally supported by a substrate 1807, and incommunication with at least one controller 1808 and/or timer/clock 1814or other control device. The controller 1808, which preferably includesa microprocessor arranged to implement a machine-readable instructionset, is arranged to receive power from a power source 1812. Operation ofthe lighting device 1800 may optionally be responsive to at least oneoutput signal of one or more sensors 1813 (e.g., arranged to senseelectrical, optical, and/or thermal properties and/or environmentalconditions) in communication with the controller 1808. Operation of thelighting device 1800 may optionally be responsive to an output signal ofa timer or clock 1814. For example, a timer (or alternatively a clock)1814 may be arranged to trigger switching between a first operating modeand a second operating mode, wherein in the first and second operatingmodes the combined emissions of the first LED component and second LEDcomponent provide the same or similar chromaticities (e.g., each havinga CCT within a specified number of MacAdam ellipses of a target CCT),but have melatonin suppression effects that differ by a predeterminedthreshold (e.g., at least about 5%, 10%, 15%, 20% 25%, 30%, 35%, 40%,50% or more). Each solid state emitter component 1801A-1801X, andpreferably different solid state emitters within or associated with eachsolid state emitter component, may be independently controlled. AlthoughFIG. 18 illustrates each lamp 1801A-1801X as being supported by a commonsubstrate 1807, in certain embodiments, different lighting devices of anarray or group 1800 may be supported on different substrates optionallyspatially segregated from one another. The controller 1808 or othercontrol element may be integrated with a lighting device 1800 includingone or more of the solid state emitter components 1801A-1801X, or thecontroller 1808 may be located remotely from the solid state emittercomponents 1801A-1801X. In certain embodiments, the controller 1808 mayinclude a communication element (not shown) arranged to receive signalsfrom a network, remote device, or wireless link to affect control oroperation of the lamps 1801A-1801X. The array or group 1800 may comprisea backlight, light fixture, group of lighting devices or light fixtures,or other desirable implementation as described or suggested herein.

Embodiments as disclosed herein may provide one or more of the followingbeneficial technical effects: permitting adjustment of melatoninsuppression characteristics of lighting devices; permitting adjustmentof melatonin suppression characteristics of lighting devices whilemaintaining acceptably high CRI for a desired end use; permittingadjustment of correlated color temperature and also permittingadjustment of melatonin suppression characteristics at different CCT;and permitting a user to identify a specified time period for switchingbetween melatonin suppressing effects of backlights and backlitelectronic devices. Such effects may ameliorate or reduce symptoms ofcircadian rhythm disorders or other health conditions, avoidinterference with sleep cycles, and/or enhance nighttime workeralertness and performance.

While the invention has been has been described herein in reference tospecific aspects, features and illustrative embodiments of theinvention, it will be appreciated that the utility of the invention isnot thus limited, but rather extends to and encompasses numerous othervariations, modifications and alternative embodiments, as will suggestthemselves to those of ordinary skill in the field of the presentinvention, based on the disclosure herein. Various combinations andsub-combinations of the structures described herein are contemplated andwill be apparent to a skilled person having knowledge of thisdisclosure. Any of the various features and elements as disclosed hereinmay be combined with one or more other disclosed features and elementsunless indicated to the contrary herein. Correspondingly, the inventionas hereinafter claimed is intended to be broadly construed andinterpreted, as including all such variations, modifications andalternative embodiments, within its scope and including equivalents ofthe claims.

What is claimed is:
 1. A light emitting apparatus comprising: a firstLED component; and a second LED component; wherein the first LEDcomponent and the second LED component are arranged to be operated in afirst operating mode in which combined emissions of the first LEDcomponent and the second LED component (i) are within four MacAdamellipses of a target correlated color temperature, and (ii) embody afirst melatonin suppression milliwatt per hundred lumens value; whereinthe first LED component and the second LED component are arranged to beoperated in a second operating mode in which combined emissions of thefirst LED component and the second LED component (i) are within fourMacAdam ellipses of the target correlated color temperature, and (ii)embody a second melatonin suppression per hundred lumens value that isat least about 10 percent greater than the first melatonin suppressionper hundred lumens value; and wherein the light emitting apparatuscomprises at least one of the following features (a) and (b): (a) atleast one of the first LED component and the second LED componentcomprises at least one LED arranged to stimulate emissions of at leastone lumiphoric material; and (b) combined emissions of the first LEDcomponent and the second LED component when operated in the firstoperating mode embody a color rendering index (CRI) value of at leastabout
 80. 2. A light emitting apparatus according to claim 1, wherein atleast one of the first LED component and the second LED componentcomprises at least one LED arranged to stimulate emissions of at leastone lumiphoric material.
 3. A light emitting apparatus according toclaim 1, wherein the first LED component comprises at least one firstLED arranged to stimulate emissions of at least one first lumiphoricmaterial, and wherein the second LED component comprises at least onesecond LED arranged to stimulate emissions of at least one secondlumiphoric material.
 4. A light emitting apparatus according to claim 1,wherein combined emissions of the first LED component and the second LEDcomponent when operated in the first operating mode embody a colorrendering index (CRI) value of at least about
 80. 5. A light emittingapparatus according to claim 4, wherein combined emissions of the firstLED component and the second LED component when operated in the secondoperating mode embody a color rendering index (CRI) value of at leastabout
 30. 6. A light emitting apparatus according to claim 1, wherein atleast one of the first LED component and the second LED componentcomprises a principally blue LED having a peak wavelength of from about455 nm to about 480 nm.
 7. A light emitting apparatus according to claim1, wherein at least one of the first LED component and the second LEDcomponent comprises a principally blue LED having a peak wavelength offrom about 465 nm to about 480 nm.
 8. A light emitting apparatusaccording to claim 1, wherein at least one of the first LED componentand the second LED component comprises a principally cyan LED having apeak wavelength of from about 481 nm to about 505 nm.
 9. A lightemitting apparatus according to claim 1, further comprising at least onecontrol circuit arranged to adjust supply of current to at least one ofthe first LED component and the second LED component to operate thefirst LED component and the second LED component according to the firstoperating mode or the second operating mode.
 10. A light emittingapparatus according to claim 1, further comprising at least one userinput element arranged to receive a user input to trigger switchingbetween the first operating mode and the second operating mode.
 11. Alight emitting apparatus according to claim 1, further comprising atimer or clock arranged to trigger switching between the first operatingmode and the second operating mode.
 12. A light emitting apparatusaccording to claim 1, further comprising a photosensor arranged totrigger switching between the first operating mode and the secondoperating mode.
 13. A light emitting apparatus according to claim 12,wherein the photosensor is arranged to receive ambient light, and isshielded or otherwise placed to prevent receipt of direct lightemissions from the first LED component and the second LED component. 14.A light emitting apparatus according to claim 1, wherein the secondmelatonin suppression per hundred lumens value is at least about 20percent greater than the first melatonin suppression per hundred lumensvalue.
 15. A light emitting apparatus according to claim 1, wherein thesecond melatonin suppression per hundred lumens value is at least about30 percent greater than the first melatonin suppression per hundredlumens value.
 16. A light emitting apparatus according to claim 1,comprising at least one of the following features: a single leadframearranged to conduct electrical power to the first LED component and thesecond LED component; a single reflector arranged to reflect at least aportion of light emanating from each of the first LED component and thesecond LED component; a single submount supporting the first LEDcomponent and the second LED component; a single lens arranged totransmit at least a portion of light emanating from each of the firstLED component and the second LED component; and a single diffuserarranged to diffuse at least a portion of light emanating from each ofthe first LED component and the second LED component.
 17. A lightemitting apparatus according to claim 1, wherein the target correlatedcolor temperature comprises a value selected from the range of fromabout 2500K to about 6000K.
 18. An electronic device including abacklight comprising the light emitting apparatus according to claim 1.19. A light fixture comprising the light emitting apparatus according toclaim
 1. 20. A method comprising illuminating an object, a space, or anenvironment, utilizing a light emitting apparatus according to claim 1.21. A light emitting apparatus comprising: a first LED component; and asecond LED component; wherein the first LED component and the second LEDcomponent are arranged to be operated at or near a first targetcorrelated color temperature in a first operating mode in which combinedemissions of the first LED component and the second LED component (i)are within four MacAdam ellipses of the first target correlated colortemperature, and (ii) embody a first melatonin suppression milliwatt perhundred lumens value; wherein the first LED component and the second LEDcomponent are arranged to be operated at or near the first targetcorrelated color temperature in a second operating mode in whichcombined emissions of the first LED component and the second LEDcomponent (i) are within four MacAdam ellipses of the first targetcorrelated color temperature, and (ii) embody a second melatoninsuppression per hundred lumens value that is at least about 10 percentgreater than the first melatonin suppression per hundred lumens value;wherein the first LED component and the second LED component arearranged to be operated at or near a second target correlated colortemperature in a third operating mode in which combined emissions of thefirst LED component and the second LED component (i) are within fourMacAdam ellipses of the second target correlated color temperature, and(ii) embody a third melatonin suppression milliwatt per hundred lumensvalue; wherein the first LED component and the second LED component arearranged to be operated at or near the second target correlated colortemperature in a fourth operating mode in which combined emissions ofthe first LED component and the second LED component (i) are within fourMacAdam ellipses of the second target correlated color temperature, and(ii) embody a fourth melatonin suppression per hundred lumens value thatis at least about 10 percent greater than the third melatoninsuppression per hundred lumens value; and wherein the second targetcorrelated color temperature differs from the first correlated colortemperature by at least about 300K.
 22. A light emitting apparatusaccording to claim 21, wherein the first LED component includes multipleLEDs and the second LED component includes multiple LEDs.
 23. A lightemitting apparatus according to claim 21, wherein at least one of thefirst LED component and the second LED component comprises at least oneLED arranged to stimulate emissions of at least one lumiphoric material.24. A light emitting apparatus according to claim 21, wherein the firstLED component comprises at least one first LED arranged to stimulateemissions of at least one first lumiphoric material, and wherein thesecond LED component comprises at least one second LED arranged tostimulate emissions of at least one second lumiphoric material.
 25. Alight emitting apparatus according to claim 21, wherein combinedemissions of the first LED component and the second LED component whenoperated in at least one of the first operating mode and the thirdoperating mode embody a color rendering index (CRI) value of at leastabout
 80. 26. A light emitting apparatus according to claim 25, whereincombined emissions of the first LED component and the second LEDcomponent when operated in at least one of the second operating mode andthe fourth operating mode embody a color rendering index (CRI) value ofat least about
 30. 27. A light emitting apparatus according to claim 21,wherein combined emissions of the first LED component and the second LEDcomponent when operated in each of the first operating mode and thethird operating mode embody a color rendering index (CRI) value of atleast about
 80. 28. A light emitting apparatus according to claim 27,wherein combined emissions of the first LED component and the second LEDcomponent when operated in each of the second operating mode and thefourth operating mode embody a color rendering index (CRI) value of atleast about
 30. 29. A light emitting apparatus according to claim 21,further comprising at least one control circuit arranged to adjustsupply of current to at least one of the first LED component and thesecond LED component to operate the first LED component and the secondLED component according to the first operating mode, the secondoperating mode, the third operating mode, or the fourth operating mode.30. A light emitting apparatus according to claim 21, further comprisingat least one of the following elements (A) to (C) arranged to triggerswitching between the any of the first through fourth operating modes:(A) at least one user input element arranged to receive a user input;(B) a timer or clock; and (C) a photosensor.
 31. A light emittingapparatus according to claim 21, wherein the first LED componentcomprises at least one first LED arranged to stimulate emissions of atleast one first lumiphor, and the second LED component comprises atleast one second LED arranged to stimulate emissions of at least onesecond lumiphor.
 32. A light emitting apparatus according to claim 21,comprising at least one of the following features (i) and (ii): (i) thesecond melatonin suppression per hundred lumens value is at least about20 percent greater than the first melatonin suppression per hundredlumens value, and (ii) the fourth melatonin suppression per hundredlumens value is at least about 20 percent greater than the thirdmelatonin suppression per hundred lumens value.
 33. A light emittingapparatus according to claim 21, comprising at least one of thefollowing features: a single leadframe arranged to conduct electricalpower to the first LED component and the second LED component; a singlereflector arranged to reflect at least a portion of light emanating fromeach of the first LED component and the second LED component; a singlesubmount supporting the first LED component and the second LEDcomponent; a single lens arranged to transmit at least a portion oflight emanating from each of the first LED component and the second LEDcomponent; and a single diffuser arranged to diffuse at least a portionof light emanating from each of the first LED component and the secondLED component.
 34. A light emitting apparatus according to claim 21,wherein each of the first target correlated color temperature and thesecond target correlated color temperature value is selected from therange of from about 2500K to about 6000K.
 35. A light emitting apparatusaccording to claim 21, wherein the second target correlated colortemperature differs from the first correlated color temperature by atleast about 600K.
 36. A light emitting apparatus according to claim 21,wherein the second target correlated color temperature differs from thefirst correlated color temperature by at least about 1000K.
 37. Anelectronic device including a backlight comprising the light emittingapparatus according to claim
 21. 38. A light fixture comprising thelight emitting apparatus according to claim
 21. 39. A method comprisingilluminating an object, a space, or an environment, utilizing a lightemitting apparatus according to claim
 21. 40. A backlight arranged toilluminate a display panel arranged to display at least one of imagesand text, the backlight comprising: a first LED component; a second LEDcomponent; and a timer or clock arranged to trigger switching between afirst operating mode and a second operating mode; wherein in the firstoperating mode the first LED component and second LED component generatecombined emissions that (i) are within four MacAdam ellipses of a targetcorrelated color temperature, and (ii) embody a first melatoninsuppression milliwatt per hundred lumens value; and wherein in thesecond operating mode the first LED component and second LED componentgenerate combined emissions that (i) are within four MacAdam ellipses ofthe target correlated color temperature, and (ii) embody a secondmelatonin suppression per hundred lumens value that is at least about 10percent greater than the first melatonin suppression per hundred lumensvalue.
 41. A backlight according to claim 40, wherein at least one ofthe first LED component and the second LED component comprises at leastone LED arranged to stimulate emissions of at least one lumiphoricmaterial.
 42. A backlight according to claim 40, wherein the first LEDcomponent comprises at least one first LED arranged to stimulateemissions of at least one first lumiphoric material, and wherein thesecond LED component comprises at least one second LED arranged tostimulate emissions of at least one second lumiphoric material.
 43. Abacklight according to claim 40, wherein the timer or clock comprises auser-adjustable timer.
 44. A backlight according to claim 40, furthercomprising at least one control circuit arranged to adjust supply ofcurrent to at least one of the first LED component and the second LEDcomponent to operate the first LED component and the second LEDcomponent according to the first operating mode or the second operatingmode.
 45. A backlight according to claim 40, wherein the secondmelatonin suppression per hundred lumens value is at least about 20percent greater than the first melatonin suppression per hundred lumensvalue.
 46. A backlight according to claim 40, wherein the secondmelatonin suppression per hundred lumens value is at least about 30percent greater than the first melatonin suppression per hundred lumensvalue.
 47. A backlight according to claim 40, wherein the targetcorrelated color temperature comprises a value selected from the rangeof from about 2500K to about 6000K.
 48. An electronic device comprisinga backlight according to claim 40 and a display panel arranged to beilluminated by the backlight.
 49. A method comprising illuminating adisplay panel utilizing a backlight according to claim 40.